I don't think the AC will make much of a difference, and certainly not a big one -- the simple fact is that the AC compressor is automatically disengaged when the throttle is wide open, regardless of the AC setting in the cabin. So the A/C compressor would only kick in for the split second between shifts ... assuming you are lifting the throttle between shifts. As soon as that pedal hits the floor, the compressor disengages.
You can test this yourself... turn on the AC, put the car in 5th (or dont if you are in a hurry!) and go full throttle on a hot day... you will feel the ac unit start to blow warm air, because the compressor is disengaged.