one thing you have to remember, if you put the nitrous just in behind the carb like most kits do and that feeds the crankcase . now when you let off on the nitrous you still have to burn whatever is left in the crankcase and that is pretty wild when things go wrong like throw the chain stuff like that enough after a good run it 3 to 4 seconds of hell. I guess it depends on how much you are fogging in also but when we did it we went full out , balls to the wall. one thing is a rpm limiter that you can set , it helps alot cause even with the throttle closed after your run until it burns everything in the crankcase the motor can still turn 14000 , 15000 rpm's or higher.
Now if you put the nitrous in threw the head it would be alot easier to control, but anyways have fun