I have a 642 revolver and an LC9 pistol. I bought the auto some years after the 642 and I find the auto easier to shoot but after carrying both I find the slight weight difference to be quite noticeable, the 642 seems much lighter than the LC. The difference is about 3 ounces, I wouldn't have thought I could tell the difference in a pocket but I can. Will continue to use the 642 as my pocket gun.
I don't know how much difference there would be in a holster.
Any ideas on this?