I think it depends on the aspects of the individual models. T-shirt in the summer time requires a lot of thought with revolvers in regards to grips, cylinder width, loaded weight and carry style. Barrel length not so much.
I never thought much of these snubby L frames, GP-100s and God-forbid N frames, especially with big "combat" grips. Nice to look at, shoot well at the range. But it's a helluva big fat short round chunk of iron to be packing round. A 4" revolver in that size and weight range is as easy to carry. In LE I carried a 4" model 27 for several years - concealed. As soon as automatics were authorized, I dropped that like a hot potato. Very nice revolver, but a .45 steel-frame semi conceals better.
Had a peck of Charter Arms Bulldog 5-shot .44 Special revolvers. Most had 2.5" barrels. Then I bought a 3" Classic. Everywhere I could carry the 2.5", I could also carry the 3". This includes appendix IWB carry, and strongside OWB in an appropriate holster. Neither of these are pocket guns for modern-day pockets. Still my favorite 3" carry revolver and I pack it frequently IWB.
I also carried a 2-1/2" Model 19-5 back in the day of LE work. I didn't conceal any better than the 3" Model 13-3 I was issued. A few years ago, I bought a 2" Model 10-7... even though the frames and cylinder and grips were identical, that K-frame carried the easiest because it was slightly lighter, slighter shorter, and didn't have snaggy adjustable sights.
For awhile I had some Ruger SP-101s, with 2" and 3" barrels. Disliked the 2" gun as it didn't conceal any better than the 3", was nearly as heavy, and was more difficult to be accurate with.
Currently have a 3" barrel Colt Viper, and an almost identical frame/cylinder sized 2.2" barrel Charter Arm Police Undercover (also all steel), both 6-shots. With small frame-sized grips, the Charter is easier to conceal. The Colt has larger grips, and due to the weight range of these two guns, it doesn't work as well appendix carry.