I think I might like to get holsters for my guns. I have a scoped Mark II and a 6" GP100. How in the heck does one go about getting the correct holster for a gun? I was at a gun store today and they had dozens and dozens and DOZENS of holsters. I noticed there were ones specifically made to hold a scoped gun, but other than that, I wouldn't know which would fit my guns. Especially since they had a bin of used holsters that looked very nice to me. Nice leather ones. How does one choose a holster?