David, Following your lever Frame building with interest. Your latest version is an excellant design, my only concern is the Micro switch attached to the lever may cause premature failure of the wiring due to lever movement. I wonder if you'd cnsidered something along the ines of Leslie Bevis-Smith (MERG) design where the micro switch is fixed? I'm sure that your current design could easily be adapted.
regards
David (Pannier Tank)