With the shaft position sensor mounted in this position:
There’s no way to get a screwdriver into the trimpot that adjusts the sensor’s trip point.
A few minutes with tin snips, nibbling tool, and square file produced a small wrench:
One side of the wrench has a 45° bend that made tweaking the pot just slightly easier.
The proper trip point turned out to be about 90° away from where the trimpot started, with the level midway between the detection points for shiny metal tape and the cutout side of the counterweight.