The tuning window for model engines seems to be pretty broad. From one day to the next you might need a click or two richer or leaner but it is pretty consistent. I think it's the methanol. I had a drag car in the late 80s, initially running gasoline. If we left the jetting alone we had to change the dial-in on the car quite a bit from round to round. Or, we could constantly rejet the carburetors to try to keep it consistent. Switching to methanol (lots of money to modify two carbs) made the car much more consistent without changing jets all the time.