Hi Richmond,
It's all very well updating the Dragonfly ignition to 12 volt with a twin output coil to get over the HT problems and an 'electronic' unit to reduce the load on the points, but this still does not get over the basic problem with the Miller distributor - the inadequate bearings!! Without some modification to the bearings, the spindle can still float around, with the result that the timing remains very erratic. Back in the 80's, I converted my Dragonfly to twin Lucas points firing twin Miller coils - the points being housed in a home brewed unit with needle roller bearings and utilising the original Miller bobweight assembly. This set up has now covered in excess of 35,000 miles and has proved to be utterly reliable - the points only needing adjustment twice in that time. The bike still has a slow, reliable tick over, and can still be revved out all day long, with no signs of any misfire.
Another mod that I did was to move the condenser from under the distributor cover (where it overheated) to a position on the side of the coils - I know the experts say the condenser should be as close as possible to the points, but it certainly seems happier in a stream of cooling air.
Regards,
Eddie.