After a lot of experimenting with different types of IWB holsters, from the cheapest to the most expensive, it's the cheapest one that ended up working the best for me. A $12 Uncle Mike's #36, modified for deeper carry by relocating the belt clip higher on the holster.
My daily carry gun is a 340 M&P with full-sized S&W J frame grip.
Also attached is a little graphic that I made using my 340 M&P and one of my comparably sized semi auto, the Walther PPS 9mm. (black line represents the top of the belt line) With both in their carry position - grip just at the top of the belt line, you can see how the shape of the revolver allows more of it to be carried beneath the belt line - very little to stick up and jab me in the side, especially when I'm driving the car (ie-sitting position)
After a lot of experimenting with carry guns, holsters, and methods of carry, this DAO J frame / Uncle Mike's IWB set-up works the best for me.
Sorry about the photo quality. I was using my phone cam. Poor resolution.