Nice pics.
I had a Witness Match a few years ago , but sold it because the magazines were problematic. Fast forward a few years, and now that Mec-Gar is making the mags I haven't had any problems. The red follower mags just never worked for me...
I just hand fitted a Witness Match slide in .40 S&W to my Wonder Finish upper, it wasn't nearly as bad as I thought it would be, but it did take me me a lot of time. I was very happy with the final result, there is no side-to-side play, no rattle when I shake the pistol, and slide moves effortlessly on the frame. According to the calipers, I probably removed a few thosandths more from the rear portion of the rails than I should have, but that's probably the perfectionist in me talking. While slide to frame fitting can be labor intensive, the rail in frame design seems pretty forgiving. Hopefully, I'll post up some pics and a test fire tis weekend.
A standard .38 Super conversion from Numrich went together with no fitting, but it was built with much looser tolerances than the Match slide.
If I had to do it over again, though, I'd go straight for a Witness Stock I in .38 Super.