I normally run at a 1/5 mile medium banked track. I will be running a one off event at a 3/8 mile track usually used for cars (Penton Motor Speedway). I will be running Clone Super Heavy at 400 lbs. What gear should I start with on something like this? I am thinking a 20, but I could be WAY off. Also, it is an open tire rule. I assume I would want something harder due to needing roll speed. What do you guys recommend?