Jim from what your describing you used your timming wheel to figure out where you located your sensor and magnet. It sounds to me like no procedure was used to find true tdc and you dont know if your degree wheel was set at true tdc. not really necassary to just located where you want your mag and sensor as a few degrees here or there wont matter, but very necassary to get your spark set correctly at the desired degree of 28 deg btdc. then it sounds like you installed the magnet and the sensor and no procedure was used to verify what the spark timming actually was. the engine was then run and the timming was adjusted by hand and ear to what you consider to be the sweet spot. so in all actuallity you have no idea what you timming is actually set to right?

Im not trying to beat you up on this im just trying to understand your method.