When I was looking into installing MJLJ onto my vehicle, I wondered whether I could use a small gear wheel (like a Myford lathe change gear) inside the distributor housing, to keep everything looking "stock". Wasn't possible with MJLJ as it needs a 36-1 wheel because of EDIS but I reckon with a smaller gear and a Hall-effect sensor inside the dizzy, you could have a simple and reliable setup. You'd still have to disable the mechanical advance weights inside the distributor.