This doesn't answer the exact question you asked, and I certainly won't be insulted if you simply ignore my post, but there is some possibility that there is no IWB holster that will work as well as, say, a good pancake by O'Rourke or Lobo or one of many others.
I happen to like IWB very much, for slabside pistols, and consider the Bruce Nelson/Milt Sparks Summer Special to be ideal. However, revolvers are a whole nother story. While I did carry a 2.5" M19 for a number of years in a Bianchi Pistol Pocket, by and large I have NOT been impressed with IWB for revolvers. I own quite a few Summer Specials for J, K & N revolvers, all in virtually new condition. Without digging into my several holster boxes, I believe that O'Rourke, DeSantis and Galco pancakes are the ones that have actually been used for all three frame sizes.
What works best for you will probably depend mostly on body shape and maybe almost as much on what size pants you are willing to buy. I would just like to suggest to you the possibility (fact, for me) that with revolvers IWB may not be the way to go.