Hey TC,
shoulder holsters are not very popular with, well, most crowds. I?ve tried most of the major brands, and a few custom rigs like Andrews (which is ?very? nice). The one I am most fond of is Galco?s Jackass, and it?s just pretty affordable. As for what gun, its usually been a 1911 Government down the years. I find it very comfortable and very conceable, even with just a light shirt. It is not the fastest (or safest) draw, and I would recommend something else for most people. There are good reasons for their un-popularity. But you can do a lot worse that starting with a Jackass, and they don?t break the bank.
Best of luck with it!