I don't see a problem combining the two 10.0 classes. If the race cars are on dot's, have mufflers at the rear axle, and make the drive, I think that qualifies them as a no bull 10 sec class car by the rules. If you are talking about just making the two classes 10 sec run what you brung and the drive is not mandatory the name and the series needs to be changed to Gambler or Trophy classes.
I have been to every swsscs/no bull type of "street car" race since they started in '04, either as a spectator or a racer. What has seemed to have the best turnout, spectator and entrant wise were 3 races spread out over the season and 4 classes. Outlaw, 10, 12, 14. I think the formulas is simple and already in place. I think the problem is with people trying to accommodate others who have a complaint or want a specific class so they cam participate. The only time the rules need to be revised are for safety reasons. The basic setup is clean, easy, cheap to participate.
My suggestion for growing the event was to take the entrance money from the 12, and 14 sec classes and give that to the outlaw, no bull cars. Give the 12/14 sec guys trophies. When the big dogs come out to play everybody wants to watch, whether it be jet cars on 4th of July, or Kennan VS Sherbring (sorry for sp if i am off) outlaw final, ice skatin down the dusty ol Alb 1320.