Since you mentioned your preference for a revolver, that you are a relatively large guy, and your interest in a Colt New Service in .45 L Colt; consider finding a S&W model 25 or model 625 in .45 LC.
It might be cheaper, and you might like it.
I hope you enjoy the learning experience you have embarked upon.
NRA Life Member - Orange Gunsite Member - NRA Certified Pistol Instructor
"When plunder becomes a way of life for a group of men living together in society,
they create for themselves in the course of time a legal system that authorizes it and a moral code that justifies it." Frederic Bastiat