I have taken his class and several followup classes. We have gotten to know each other, and I consider him a friend as well as my mentor in archery. I don't think you need to watch any of his videos in advance, unless you particularly want to. What I do recommend you do is to listen very carefully to everything he says, and try to take everything literally, not colored by any preconceptions of what you think good archery form should be.
I wasn't sure what archery style I wanted to use when I decided to get formal archery training, so I took Rick's class and some other ones from other well-known archery instructors. I decided there were good points from all of them and I picked the points I liked the best from all three, like you would from a menu in a Chinese restaurant. That was a big mistake, and screwed up my shooting for a couple of years until I learned that you need to adopt one style of shooting and stick with it unless you're good enough to invent your own style, which I wasn't.
I finally decided I liked Rick's style the best, and had to relearn it. Fortunately, Rick is very patient and is used to having to reteach people his style after they try to mold it into something different. So learn all you can from his two day class and try to apply everything you learn exactly the way he teaches it. After a few years, if you want to try some different style, do the same thing: apply everything they teach you and forget the things Rick taught you. If you decide you like Rick's style better, you can go back and relearn it, but I don't know how you can decide which style you like best without trying them, unless you are lucky enough to know from the git go that Rick's style is the one for you and you never have any desire to try something different.