Lubrication
Another thing to look at would be lubrication and ammo. My Springer needed extra lubrication on the rails at the 100 round mark when I shot Remington bulk 230 grain FMJ (dirtiest 45 I have ever shot, but cheap). I now spray it down with Gun Scrubber at around 100 rounds and...
Colt Delta Elite, S&W 1076 and 1006. Sold my 610s awhile back.
Re a 10 mm barrel for the Glock 22, I don't believe it would work. The 40 was designed to fit in guns designed around the 9 mm cartridge. The 10 mm cartridge OAL is too long to fit.
Living in Florida means it depends on the weather and where I am going. If I go to the beach a Keltec P3AT in a pocket holster is it. At the other end of the spectrum is a Coonan Classic 357 in a pancake holster with 2 extra mags.
Size does matter
If I carry at 2 the gun is a compact, Glock 27 or smaller. Anything larger is uncomfortable. I normally carry a full size handgun at the 3 to 5 position.
Regarding shooting your parts when carrying at the 2 o'clock position. It does make the finger off trigger safety rule...