I'm tired of the crumby shimano 105 RD on mine. With the shifter in friction mode shifting isn't too bad, but even w/ the low adjustment screw backed all the way out the RD isn't close enough to the wheel to use the largest rear sprocket. Does any shimano 600 RD have enough range of motion for me to use all seven sprockets, or do I need to use a period correct version? Do any other brands of RD have enough range of motion to use in this case?