Paul,
I think you have to be very careful in saying we only race Mardaves in an endurance race during our Xmas meeting as you are then alienating over half of the club's members.
Maz, I think your suggestion is spot on in terms of how we handle running both Touring Cars and Minis.
I would therefore suggest that those who wish to race at the Xmas party meeting let us know and which car they would like to run, either TC or Mini. I would then put all the F1 drivers into a hat, F2 into a hat and so on then select at random 3 teams made up of both TC and Mini drivers with a mixed range of skill levels to race. As Maz cleverly suggests, the race is split into two parts - TCs and Minis not then racing side by side.
We can then fine tune the rules to keep it simple and easy to follow and then we can all enjoy the nights racing
I would also like to suggest a last man standing race. This would be loads of cars on track and you just race until only one is left. Zero tolerance on contact - if you hit another car your out. If you crash out the marshall removes your car and your out. Just keep driving around the track until your the last one running. To prevent someone driving very very very slowly and therefore conserving batteries, we could have a minimum lap time that drivers must keep to - that'll be interesting for the drivers