Throttle Boss (and other brands) is a rubber piece that wraps around the throttle and lets one push with the palm to open the throttle instead of turning it with the fingers. Helps a lot with numb/claw hand. Should work fine with bar end mirrors. Jeff, I couldn't believe it, but I got 55mpg at those speeds (although my FCRs may be a teensie bit lean at cruising speed throttle opening). I have a Sargent saddle too, and CycleCat bars, which really improve the comfort.