Also to answer your other question. IAME masters looks to be a IAME engine class only where as the others include the usual suspects in Tag(rotax,x30,Rok etc). And I would like to say the masters class would be more civilized with lots of clean racing due to age group. I def would recommend coming out and watch the racing. That will give you a very good idea how each class is.
Thanks again. I’ll definitely head up there. That track looks insane.