That thought had crossed my mind earlier in the day. Then I got home and the thrill of something new drove it from my mind... But you are correct, it will not take timing adjustments into consideration. Weird though that the timing on the motor just happened to be the right timing to make the test work.

Coming up with a way to do this without a slave motor is going to be tricky. The back emf will have to be isolated from the supply voltage. I will have to do a lot more reading to figure this out.