CF is right on. If you don't have strict rules someone will come out with a high powered engine and slaughter everyone. It's ante up or get out time. Someone comes out with a really light plane and slaughters everyone. Same thing. If you start low tech like spads etc and someone comes out with an Avenger and slaughters everyone. It 's ante up again and learn new building techniques.

This is one of the main reasons RCCA was created to try and have the same rules in place all over the country.

If you want high speed and high performance and high dollars go with B class. If you want lower speeds and lower tech and less shop time, go SSC.

There's nothing wrong with creating your own local combat class but you'll miss out on a lot of fun if you can't use the same equipment at a nearby meet.