If it were me, I would just carry the extra mag. Carrying an extra piece would be too much of a worry for me. Hell, I even packed my P22 last weekend when we went to Thatcher Park for a hike and the thing was kind of uncomfortable (I wasn't using a holster, just a tuck in the front). I don't carry very often, only when we go somewhere that I consider to be a possible risk area, so maybe I am just not used to the metal against my gut. I think carrying a 3rd mag would be ok though in lieu of a 2nd piece. By the time you have expended your second mag, hopefully you would have found cover by then if you've had to use that many rounds. You should be able to safely load your third.