Inside is uncomfortable but more secure & concealable. So I'd guess next best thing is fat boy carry.
Pocket is next best but only with a trigger guard the grabs the pocket & falls off when you draw it out.
I'd never ankle carry. It just feels like every time you step its gonna fly out- even when tucked inside a cowboy boot.
If you could pull it off, the most comfortable & concealable would be under the shoulder, cross draw.
Rugar SR9C gets my vote. Not a Glock fanboy.