With the different holsters I have, I can appendix carry any firearm I want to. Sig P226, P6, Glock 19, Glock19 with Lightguard, J frame S&W, and now a Shield 9mm.
I am currently working with Doyle Burdette of Burdette Custom holsters on a new design. I have been wearing the second prototype since Friday, have made a couple suggestions for mods and will be getting another prototype in a week or so.
The key I have found is the holster design must pull the gun butt toward you while tilting the muzzle slightly away from the body.
You will need to develop less sensitivity where the muzzle hits which will sometimes become sore the first couple days. I found it goes away.
I am by no means thin. (Big Boned
) Over the years (yes, I am old) I have tried a lot of different types of holsters and even consulted at one time with John Bianchi on a design that he eventually made. (Remember the upside down shoulder holster?) You have to be willing to compromise something to get concealment and fit. Eventually, you find what works.
Anyone wishing to try something I have for the guns listed above, let me know. I even have a left hand J frame holster from Alessi (RIP LOU) and a left hand for my P6 from Burdette (A great guy to deal with).
Hope this helps.