I carry a 442 with a technaclip to the gym. Squat 315, deadlift 405. Both with this at 4 o'clock iwb
If you want to be almost naked, an aluminium J cannot be beat. 38 or even 357, small, light, not an auto.
Before you go up to any K frame at all, try and find a kimber K6s. It's steel, 6 shots, and closer to a J frame than a K frame.
As far as carrying, I go L frame, then skip down to my K6, then a 442, if I want a gun without having a gun, then I carry a mini revolver.
Anybody that tells you to wear a fanny pack has no self-respect, and also gave you good advice. I'll never do it, but I would also never carry an auto.