I'm not fat. Not even big boned. But if you like a 3" J frame, you might want to try one of the Safety Speed holsters meant for such. I've worn one on a regular belt. Works great and is very comfy. Safety Speed is now defunct, but an Ebay seller bought out their remaining stock and lists their stuff at good prices on there.

If you just want to try a shoulder rig, and not invest much, you could try one of the UTG rigs. They're "okay", but work better with autos.