two things;
1. PJ showed me this years and years ago, but it might work,
http://yarchive.net/car/air_induction.html
2. second i've noticed tuning a few cars that going from say 12:1 afr at cruise to 15:1 at cruise "looses power", my gsl-se particularly used to do this when the sensor in the radiator switched it into closed loop, the car would feel torquey, and then when it switched to closed loop, "loose power".
but if you think about it backwards, you say it takes X amount of fuel to go 25mph, and @12:1 afr, you have to open the throttle Y percent. when you switch to 15:1 afr, the amount of fuel you need to go 25mph is THE SAME, but the amount of air is bigger so you need to open the accelerator MORE. y+(15:1/12:1)
i hope that makes sense, its easy just to think of the gas pedal as a linear power delivery lever, but with a carb particularly, you can get fuel and air to be separately metered (weather you want it or not!).
a lot of new cars in europe have a "stratified charge" mode, where i think the throttle opens, and its fuel controlled like a diesel. i don't know exactly how you'd implement it on a rotary...
mike