Since Roar will not be there Wednesday for a controled practice I would suggest that you run a controled practice by class. Each class gets half an hour or so on the track (less or more time depending on entrys for that class) so mod guys aren't running over sportsmans TC guys or 17.5 12th scales, thats just not fun for anyone.
This way you can go out run some laps make changes and go back out with in that classes time allowed.