Jacketed bullets are tough enough to do some self-centering in the forcing cone, so a slightly oversize throat doesn't seem to bother them.
My 1" RH, actually only does under an 1" for 5 out of 6 shots with one chamber always low and right. The barrel's groove diameter is right at about 0.429". As it came from the factory (the way the group below was shot), all throats would pass a 0.430 pin gauge, five would pass a 0.431 pin gauge, and one would pass a 0.432 pin gauge. That last chamber throat was three thousandths over groove diameter and was responsible for the flier in the group below, shooting 0.429 jacketed bullets. But clearly, up to two thousandths over groove, there was no issue. And, even including the flier, for a 50 yard group (off bags with scope sight), it isn't bad. On Target says the 5 shot cluster is at 0.685" diameter, C.T.C., while that last one opens the group to 01.495".
Anyway, in your shoes I would not hesitate to open the cylinder throats to 0.4310" (Dave Manson's
standard throater for 44 cal, as sold by Brownells). Then you are set for lead bullets whether you ever shoot them or not, though you will want to get them sized to 0.4305-0.4310" for best effect. Hornady makes all their jacketed 44 cal bullets 0.430", so if there is any element of imbalance affecting your group size, shoot those.
Now, does that mean this is all you have to do? Alas, no. My RH also happened to be one of three at the shop at the time I got it, so I was able to pick the one timed to best center the chambers in the bore and that had the most even looking barrel/cylinder gap. In addition, after that group was shot, I hand lapped it to remove a bore constriction at the frame for shooting lead. I did not firelap it because wanted to be sure the bore kept the dimensions that produced those 5 good grouping shots. So I lapped the rest of the bore only using 1200 grit SC lapping compound followed by some Flitz, just to smooth the rough spots a little.