I used the Boyer dual coil, which was slightly easier since the mounting points are on the bottom (top?) face. I made up a small U shape bracket which used the existing coil mounting holes, and mounted the coil on the new bracket. The only problem is that you have to choose between a neat installation with the HT leads coming out the rear, and the 12V feed on the front where it's exposed to the weather, or protectthe 12V feed and have an annoying loop of HT cable from the front of the unit back to the plugs. Not really happy with my solution, will be reworked this winter.