1. I've seen folks shoot the full size Ruger version and do just fine.
2. Do you want to shoot a carry gun in IDPA? If so, I see folks and I've shot a Glock 26 and did respectably for me and got trigger time with it.
Jim has a good idea. I shoot a G19 lots of the time, carry the 26 and shoot it once in awhile. I also shoot a 1911 or even a revolver as I regard IDPA as practice trigger time with carry guns and/or guns I like.
Of course, I'm not going to win so it might be cognitive dissonance.
Have fun - where in TX, BTW?