First off -- wow, you take an awfully skilled and beautiful photo! Some people make it look soooo easy to snap great pictures. Let's just say that I can shoot handguns far better than I can capture them in a picture.
745's are totally gorgeous handguns and for a long time I believe they have been under-valued sleepers in the market. Yours at $750 is a totally solid buy and once you start shooting it and really fall in love with it, you will have no regrets at that price.
If possible on re-assembly, see if perhaps rotating the hammer block thumbs safety just a wee bit doesn't add a bit of clearance? I know that of my two 745's, my IPSC/DVC exhibits slight frustration like you detail, but I'm sure that mine isn't as bad. My other non-IPSC 745 is easy and no hassle, but that is a "looser" pistol all around.
Can't wait to hear a range report. Like most of us in these forums, I am thoroughly addicted to 1-2-3rd Gens, but for the life of me, I cannot understand why it seems we discuss the totally cool -745- so rarely.
I believe it is not only an under-valued sleeper in the market, but also right here in these discussions. I think some hardcore S&W pistol fans have overlooked this fantastic model.