I have a stock xtx except for a skins exhuast, I have 14.5 rollers in clutch, Im going out west to ride at 8-10000 feet, I have heard that the smaller rollers you will loose rpms at top end, I want to keep the smaller rollers in to smooth out take off, I am going to remove all rivits from weights, what color primary spring and helix angle would work best at this alt??????