I have the SA version for my 75 Shadow, and it fits snug and draws fine. The only problem I've seen is finish wear. The finish wear is more than expected with draw and shoot competition. This is a heavily used pistol and holster, and I expect wear; but it happened FAST: 1 1/2 inches along the flats on the slide and 1+ inches inches along the bottom of the frame with this combination.
Heating the holster slightly in these areas with those areas shimmed a little and in the holster, might have been a smart thing. YMMMV
If the 40 option is just slightly bigger, I'd try that first. YMMV
I'm not excited about finish wear as this a tool for me, but was surprised how fast it wore.