Here's the shot of it running.
I built a fiberglass mount inside the cowl and then just glued the hall effect sensor so that it was about 2mm off the nuts. This gives you a little play if you use an electric starter and the shaft moves backwards. The sensor usually detects the large counter balance used on the bottom of crank shafts, now it is sensing each of the two nuts as they pass hence the necessity to up the ratio.
Hope this is helpful, I didn't know what thread best to post the findings on.
KKKKFL