I would find a local gun shop that has them in stock for the J-frame and see if you can try sticking your gun in it.
I don't know if your Taurus will fit in a Serpa or not. I can tell you this though. Last year I was on a J-frame kick and bought several holsters for one. They were all leather and all made by the same maker. My stainless Taurus would not fit in any of them at all. The trigger guard is slightly larger than that of the J-frame.
An enlightened zeal for the energy and efficiency of government will be stigmatized as the offspring of a temper fond of despotic power and hostile to the principles of liberty.
Alexander Hamilton, author of Federalist No. 1. 10/27/1787