If ultimate performance is your goal, I would shift 5% over the RPM that peak horsepower was measured at on the dyno. The trap rpm should also be at least 5% over the peak horsepower rpm. I have to guess what your speed is based on the rpm you gave of 6200 and tire diameter 33.5 gives me a speed of 135 MPH currently at 6200 rpm. If you put 4.88 gears in it you will be at 6939 RPM going 135. If your guess on rpm in the traps is off and you go faster then the error is in your favor to get higher rpm's in the traps. I hope this gives you some info to decide what gear to use. 4.88's are going the right way unless your rpm guess is way off. Remember that this mechanical advantage will make you ET quicker and probably faster too so any increase in the MPH will make the rpm higher in the traps as well.
Bruce