So you are running the 300 crank and rods and big bore pistons correct?
I know you said you may go to flat slides but have you considered swapping over to fuel injection or does your class not allow that?
I am in the process of putting the entire ninja 300 Fuel injection system, ECU and all on a 09 250r. I think it would be fairly easy to do.... and the plus to that is you can direct tune the ECU with a tuning cable as well. Just an idea!