John, wat is the differend between yours and mine - do you have a drawing of it ?
Powerboard 2 is a professional board, Bosch was my master [8D]
The only differend with Bosch is the trigger part, they use all transistors.

In the beginning I wind me in one evening 10 torroids, all differend to test.
Next day I can't move my fingers anymore []

I'm trying now the timerboard with a optocoupler TCST2000 and the board like it more then the hallsensor.
Maybe it's also possible to use a reflector opto like CNY17, only black and white at the shaft is enough.