The guys I know who ran both C16 and Q16 where able to get the motors to run the same, but they where power adder cars
They did need to fatten it up on Q16 to go faster than on C16 also
I've seen when tuning sometimes you have to go further on the timing or mixture than when it quits going faster to get the best results, in other words try fattening it up some more beyond what you think the motor likes, like 3 to 5%
I've always used the old adage only use the minimum octane you need to go as fast as you can on N/A cars, not more octane