Forgive me the crazy answer...... but have you ever seen or thought about a handrail in Hayden duet that could slightly rotate around a " central-located" screw?.   In other words, a handrail attached to the end  only by one screw in the middle location, instead by the conventional two screws placed close to both ends of the handrail. The purpose: to obtain some advantage in reaching the outer buttons with the pinkies if needed; also letting a no-slanted handrail the possibility t