Very nice setup. It's hard to go wrong with a 4" K frame, and I love the grips.

I'm 5'8" @ 175lb s with a bit of a gut and I carried my RB 4" M10 AIWB for a while before I got my SB 4" M29, which I also carried AIWB frequently though it was a bit long and got uncomfortable occasionally. When my M29 broke and had to return to S&W I got my 3" M629 which I also carried AIWB. However, I never could find a AIWB holster I really liked for my revolvers, and have recently gotten a very nice locally made pancake that has become my primary holster.

That said, whenever I need max concealment I go AIWB. Unless in uniform I wear cargo shorts, a somewhat loose button-up shirt (not too big), and a reinforced belt, though that is far less important when carrying AIWB.