There is absolutely no way to even make an accurate guess because it depends on SOO many variables, most importantly your exact clutch setup and how aggressive it is. A clutch setup that grips the belt with silk gloves will behave differently to gear changes than a more aggressive setup that grips the belt hard will. Also if the sled backshifts well rpms might not change at all with a gear change because it will just respond to the change in load as it should. As you can see, there are A LOT of variables, that is only the beginning. Depending on exactly what point of the shift curve you are overrevving at determines where in the flyweight you want to add weight. If you overrev right out of the whole but it settles down on top end to where it should, just add weight to the inner hole. If rpms are good out of the hole but overrev on top end add weight to the outter hole. Start off with a fresh primary spring and belt before you start making changes. And rough up your sheaves good with a scotch brite pad, then clean the clutches good with hot soapy water and dry with compressed air. Also make sure alignment and center to center are within spec.