abu, i like using a small horn slipped over the mixture screw (in flight mixture control horn) run a push rod or throttle type flex cable into the cockpit if open cockpit or access hath. you can push in and out to tune mixture. you can usually use a existing control in the cockpit like mixture knob or cabin heat knob for the control.
have your engine tuned as well as you can and then use the control for fine tuning for weather changes. i once used the throttle control in a cub for the tuning. just open the door and move the throttle for mixture. jeff