As for choke constrictions - IC, LM, & M will cover just about anything you could run into. A SK will be handy, but not necessary.
There are coaches all over - some balk at the cost, but there are good ones who will do small group - (2 or 3) and your cost is a little less. Then there is getting your gun fitted - if your coach does that as well, even better.
Even at a few hundred, IF you're going to do this for a long time and invest thousands or tens of thousands over that time period, a few hundred to "learn it right" seems like a bargain