The first thing I would do, is get a hold of a 2" revolver and shoot it with what you intend to carry in it. The steel frame guns really arent all that pleasant to shoot, and the Airweight guns and lighter guns are just downright brutal. A .22 in the same type gun will really teach you nothing about them.
I have a couple of S&W 642's, and have had a number of other similar guns, in both .38 and .357mag, and if you plan on practicing regularly, the sessions are likely to very short, if you even bother at all, once you see what they are like. While I rarely use them much any more, I still practice at least once a month with my 642's, and a box of 50 is all my hand can take at an outing, and its usually sore for a couple days after.
My Glock 26's have replaced the 642's in the backup role. They are much more comfortable to shoot with, I can shoot them better, and I can shoot them without pain for extended sessions. They also will take my 17's reloads if need be.
I think the best thing you can do, is try and find a place that rents different types of guns so you can try as many as possible, or go shooting with friends who have different guns and do the same. Find what youre most comfortable with, and shoot the best with, and thats the gun you should be looking at to carry.
“The enemy is anybody who's going to get you killed, no matter which side he is on.”
― Joseph Heller, Catch-22
Zeitgeist - The movie