I carried a Model 36 3 inch in one of those holsters as a young OSI agent early 70's. I never had a problem with it but was always worried that the gun would fall out
If you choose Trijicon and buy from them direct you can send them the slide and they will install the sights at no fee. Call their customer service to see if they can fit your slide dovetail cuts
I always prefer to use sights, but. I have used a drill with advanced shooters where I put duct tape over the sights. The point being that at 7-10 yards you can get surprising accuracy with no sights in a pinch.