SIII heater air box control, help needed

Hi, all
Fixing the piddly stuff that never quite worked well, now on the heater controls. Seems a po lost the lever between the internal heater box flap and the control wire. I have looked in the parts diagram, seen the lever and made a facsimile, but… the air box flap needs to rotate about 80 degrees from open to closed while the lever affords 45 degrees motion at best. The parts manual also shows a spring, but no indication how all this goes together. A spring-loaded flip-style affair similar to the rocker switches on the dash? I’m stumped.

Ha! Should have searched first. David Langley posted a perfect set of photos a year ago, it is indeed a “flipper” mechanism, on/off only.