Oh, that’s a great question, @BrophE! And the reader has picked a couple of my favorite guns!
Greg Ellifritz makes some great points - what are you going to be able to handle comfortably for that many rounds?
Personally, I’d rather be able to do all of the training with my full size firearm so I can really understand it and be able to apply it to my carry firearm in my range time after the training is over. I’ll still have to train a lot with my carry firearm, but I’ll personally be able to shoot longer, more comfortably with a full size firearm (for most people).
But we suggest people do what works best for them. Some might find it more advantageous to use their carry, some will prefer their full size firearm.