Top class and maybe 1 support class at most. I was just at the High Limit show a couple weeks ago and there was no support class. It was a Thursday after a Tuesday rainout. The place was packed and we were out by a little after 9:00pm. The entire show ran smoothly and from qualifying through the end of the feature it was about 3 hours. When I pay $40-$50 for a ticket to watch a premiere series, I have no interest in sitting around watching a bunch of filler classes use up the track. If I want to watch that, I'll spend $12 and go to their weekly show on a Saturday night. If a promoter can't get enough fans to pay for the show without relying on ther back gate, then he shouldn't book the show to begin with.