I use Boyer
on a 500 and my coils aren't insulated. Just metal clamps around the metal coil bolted to the frame with metal bolts.
I think you'll find that as long as the coil terminals aren't touching the frame, all will be well. The coils are internally insulated. One primary coil separated from the secondary inside the metal tube with some resin or something. Most have a plastic or Bakelite top that keeps the input and output end of things away from each other.
You don't need to put the coils under the tank necessarily. They can go under the seat can't they? Hide the Boyer
in the tank cavity perhaps.