Recoil should be roughly the same. I've owned and shot side by side, both a 3" and a 5" barreled Model 60 Smith. And I couldn't tell the difference with that 2" difference, let alone the less than 1" you are concerned with.
I'd opt for the 3" model and with adjustable sights, allowing a greater choice of bullet weights and the ability to zero the gun to your liking. I've also got a pair of 1-7/8" Smiths (both 637's), and find that they are no more concealable than the 3" barreled M60. It's the grip length that makes a difference, rather than the barrel length within reason.
With any J-frame Smith, good grips make a huge difference with magnum loads. For my carry purposes, I choose a good 125 gr JHP round. In both of my guns, Remington's 125 gr JHP load in the green box (not a high dollar defensive load by any means), shoots very accurately...less than 2.5" at 25 yds from rest, has manageable recoil for 2-3 cylinders, but is definitely not a 200 rounds at a single session at the range type of ammunition. Follow up shots with that ammunition require a hard grip on the gun, and concentration as the front sight comes down out of recoil.
For the most part, I like to carry with +P .38 Special loads at 125 - 140 gr's. JHP's. But many times,here on the farm, opt for Skeeter Skelton's old favorite, a good LSWC (home cast Lyman 358156GC) backed by 13.5 gr of 2400...1100 fps from my 4" M19, and a chrono'd 1097 from my 3" M60. Recoil with the latter is robust, but manageable...I put down a good 180 lb. buck with it last year, wounded earlier by a friend, and had complete penetration though the neck just below the head at 20 yds. And I was carrying the 3" M60 on that day.
BTW, I do, on occasion, carry a 4" Model 19 with full size grips...it's a bulge on the hip for sure, but I'm more confident of a first shot hit with that gun than practically any other that I own. It's a good choice during the colder months here in KY.
HTH's ... you've got a great choice there...Smith makes a great snub nose in all barrel lengths, but the 3" is my hands down favorite... they're easy to carry and accurate to use. Rod