I absolutely love threads like this. Clarifying what some take for granted, filling in assumptions and gaps in communication. This is one thing that I like about The Firing Line Forums. Knowledgeable individuals with the patience and willingness to share.
Anyhow pastor, I've been experimenting and considering this too for the last 1/2 year or so as I've been exploring shooting faster. I learned to shoot with a focus on tight groups and started with revolvers. Exploring how to shoot fast and accurately (pushing that line) with a semi auto led me to explore recoil control. And a large part of that is the grip. Like you I have noticed that for some of my guns, it seems like an optimal 1 hand grip is not optimal for a 2 hand grip for the same reason you stated: not enough space on the left side for the support hand.
Which guns? The really small ones. I have had a focus (and so has the market demand lately) for slimmer grips and slides. M&P9c, Kahr CM9, J frames, Gen 4 Glocks. I find that if the palm/heel of the support hand doesn't contact the frame optimally, it squeezes the fingertips of my strong hand which gives less recoil control and actually hurts the fingers when gripped like I mean it. If it was just pain, I could deal with it, but performance suffers too. What did I do about it?
I also considered pulling back my strong hand's middle finger to make more room for my support hand palm and to keep it from getting crushed. But then I found out that I had been acting on another assumption / instruction I'd seen in these online training videos: that the support hand should be completely thumbs forward, wrist cocked downwards to the maximum so the fingers would be pointing 45 degrees downward to the floor if they were straight, with active muscle engagement to the keep pulling the wrist that way. I shot this way for a few years (because the videos said so of course) with recoil management being sub-par. Well it turns out that if I decreased that severe angle and don't insist on the support thumb being absolutely forward (like they do on the internet) then the heel of my support hand *actually does* fit in the gap left my strong hand. May just be the shape of my hands, but bottom line is don't take the popular instruction as the gospel.
This has helped. However in my tiniest pistols, I still end up feeling like I have more finger/hand flesh present to contend with to be optimal. This brings me to another point I have recently learned.
The market for the last few years has gone for narrower thinner flatter grips. But at some point, a trade-off occurs in control, good grip for recoil management and for me this affects being able to shoot fast accurately. Grip shape matters for your given hands. Take the cross section of a Glock for example. Gen 3 glocks have a rounded front (under the trigger guard), kind of a pointed back that comes to a peak, but the sides are absolutely flat. Gen 4 Glocks have a rounded front, flatter back than Gen 3, and the sides are still flat. Same with Kahr, M&P. Flat sides don't feel palm filling (not that feeling alone matters), and don't give as much for the support hand to exert it's strength on but they are more concealable. Look at the grip on a Sig P226 or P320. The cross section is oval. The support palm doesn't have to sink as far into the valley between the tips of your strong hand and the heel. On large pistols like the Glock, the effect of flat sides can be reduced because Glocks are usually so long in the fore-aft dimension (spreading out the strong hand grip) that there is plenty of space to place the support hand. I sometimes find that slip-on grips with palm swells really change the orientation of the fingers both by expanding the circumference in general creating more space for the off-hand if needed, and a palm swell gives more meat for the support hand to clamp down on. So grip shape and grip circumference matter. Thinner/flatter/smaller is not always better depending on your needs.
Finally, something additional for you to consider: I'm convinced some pistol grips are designed with the strong hand to provide the most gripping pressure forwards and aft with fingers at the 12 o'clock and heel of the hand at 6 o'clock position. These pistols have flatter fronts and backs to the grips. But some have a very narrow and distinctive bump running down the front and/or back of the grip which do not provide much surface area to put that in the heel of the strong hand, and these pistols provide a much more solid grip with pressure coming from a more 11 o'clock and 5 o'clock position. I find that in my hands, the CZ 75 SP-01, Gen 3 Glock, and 1911 are like this. Perhaps someone with even longer fingers than mine can grip them in the same way as other pistols.
Good luck and God Bless.
Anyhow pastor, I've been experimenting and considering this too for the last 1/2 year or so as I've been exploring shooting faster. I learned to shoot with a focus on tight groups and started with revolvers. Exploring how to shoot fast and accurately (pushing that line) with a semi auto led me to explore recoil control. And a large part of that is the grip. Like you I have noticed that for some of my guns, it seems like an optimal 1 hand grip is not optimal for a 2 hand grip for the same reason you stated: not enough space on the left side for the support hand.
Which guns? The really small ones. I have had a focus (and so has the market demand lately) for slimmer grips and slides. M&P9c, Kahr CM9, J frames, Gen 4 Glocks. I find that if the palm/heel of the support hand doesn't contact the frame optimally, it squeezes the fingertips of my strong hand which gives less recoil control and actually hurts the fingers when gripped like I mean it. If it was just pain, I could deal with it, but performance suffers too. What did I do about it?
I also considered pulling back my strong hand's middle finger to make more room for my support hand palm and to keep it from getting crushed. But then I found out that I had been acting on another assumption / instruction I'd seen in these online training videos: that the support hand should be completely thumbs forward, wrist cocked downwards to the maximum so the fingers would be pointing 45 degrees downward to the floor if they were straight, with active muscle engagement to the keep pulling the wrist that way. I shot this way for a few years (because the videos said so of course) with recoil management being sub-par. Well it turns out that if I decreased that severe angle and don't insist on the support thumb being absolutely forward (like they do on the internet) then the heel of my support hand *actually does* fit in the gap left my strong hand. May just be the shape of my hands, but bottom line is don't take the popular instruction as the gospel.
This has helped. However in my tiniest pistols, I still end up feeling like I have more finger/hand flesh present to contend with to be optimal. This brings me to another point I have recently learned.
The market for the last few years has gone for narrower thinner flatter grips. But at some point, a trade-off occurs in control, good grip for recoil management and for me this affects being able to shoot fast accurately. Grip shape matters for your given hands. Take the cross section of a Glock for example. Gen 3 glocks have a rounded front (under the trigger guard), kind of a pointed back that comes to a peak, but the sides are absolutely flat. Gen 4 Glocks have a rounded front, flatter back than Gen 3, and the sides are still flat. Same with Kahr, M&P. Flat sides don't feel palm filling (not that feeling alone matters), and don't give as much for the support hand to exert it's strength on but they are more concealable. Look at the grip on a Sig P226 or P320. The cross section is oval. The support palm doesn't have to sink as far into the valley between the tips of your strong hand and the heel. On large pistols like the Glock, the effect of flat sides can be reduced because Glocks are usually so long in the fore-aft dimension (spreading out the strong hand grip) that there is plenty of space to place the support hand. I sometimes find that slip-on grips with palm swells really change the orientation of the fingers both by expanding the circumference in general creating more space for the off-hand if needed, and a palm swell gives more meat for the support hand to clamp down on. So grip shape and grip circumference matter. Thinner/flatter/smaller is not always better depending on your needs.
Finally, something additional for you to consider: I'm convinced some pistol grips are designed with the strong hand to provide the most gripping pressure forwards and aft with fingers at the 12 o'clock and heel of the hand at 6 o'clock position. These pistols have flatter fronts and backs to the grips. But some have a very narrow and distinctive bump running down the front and/or back of the grip which do not provide much surface area to put that in the heel of the strong hand, and these pistols provide a much more solid grip with pressure coming from a more 11 o'clock and 5 o'clock position. I find that in my hands, the CZ 75 SP-01, Gen 3 Glock, and 1911 are like this. Perhaps someone with even longer fingers than mine can grip them in the same way as other pistols.
Good luck and God Bless.