Your Welcome Tom, that ballpark figure came from Steve Pasteiner a long time Yamaha pipe class guy.
I see you are from MN, long haul to Grattan Twp. MI but it will be worth the trip. You could come, make a weekend of it, even if you just run on Saturday. Sunday could be used to get back home. You’ll get as many laps as you can handle in 7 hrs!
Think about it, its 2 full months before Mid-Ohio.