Don't think of it like this gun will be a 2" gun, this gun over here is a 1 1/2" gun, and so forth.
Beg, borrow, buy, rent, or otherwise procure as many guns as you can, and buy the one that you can shoot most accurately.
Until you get a lot of trigger time, find a load that your gun likes, and practice all sorts of different scenarios, one gun will almost be as accurate as another. If you find a gun that you can shoot accurately, and it's a good reliable gun, that's half the battle, right there.
Then you can start load testing, and dial it in, and see what it's capable of, once you know what you are capable of.