I "appendix carry". Both my Glock 30S and my Rock 1911 compact. I don't like having a gun behind my 3 or 9 o'clock positions, where someone behind me (say, in line at the grocery store) can get to it before I do. Ankle carry, yes, but it's a long way down and back. So for me...and to each their own...it's appendix carry.
The trade-off is that I do not carry with a round in the pipe, with either gun. Yes, that adds maybe half a second to my on-target time, but it completely eliminates an AD headed towards my nuts. So when I shoot both guns, it's from appendix carry, no round in the chamber, draw, rack, and put 2 in the torso and one in the pelvic triangle. Practice the way you plan to fight.
If you're asking "why the pelvic triangle", well...a head is awfully hard to hit, especially when it's likely moving and your stress level is north of DefCon 1. The pelvic triangle is much larger, less likely to be bobbing around, and a .45 HST anywhere in that area is probably going to break your hip and hit a major artery or vein. In short, you ain't going far, and you'll likely be out of blood when EMS arrives.
Like I said, to each their own, but that's what I do, and how I train.