I sent my number one man to one of those two day classes, paid the $600.00 they wanted for it and when he returned, confidently took on our shop truck as our first guinea pig.
Well, since then we've learned a lot. But most of the tips, techniques and little tools we picked up from watching youtube videos, and hiring help from another shop who wraps about 200 vehicles a year. (we had three vehicles we had to clear in three days. Full wraps) The help was expensive two guys six hundred bucks for the day, but well worth it.
My point is, I guess, that you'd be far better off simply working alongside a pro (if you can find one that will allow it) just helping, and accepting no pay.
You'll learn more in one day than the two day wrap class.