When I had the 26 it always felt like I drew it better and shot better with a +2 mag. But in back to back drills I would draw it faster, and my hits were generally better with the same splits with the flat mag.
I shoot a 19 better than either so for me at least its more than two or three fingers making the difference, I shoot a 45 almost identically to a 19, but shoot a 17 substantially better than either of them.