Howdy... I have a sheet of old time copper clad fiberglass board 1/8" thick. They used to etch whatever circuit design they want and it becomes a circuit board. It's really strong and the copper on each side is at least five or six thousandths thick. It is also a plate capacitor just as it is, so I was bumping around with the idea of capping both ends of my secondary with it...Then I thought what about cutting it at or around the desired capacitance it actually needs as a top load--HV end of secondary soldered to underside, and topside becomes the other leg of the capacitor. I realize that a top load acts as part of the overall capacitor of the system which includes the surrounding area in order to complete the circuit for the secondary side. So what will having a disc composed of dual sheets of copper with the same area, spaced 1/8"apart, do if it's a topload? Or I can use it as the disk that junctions between top of coil form and inner part of toroid with the HV wire soldered to disk with additional copper strip to join both sides of the disk together electrically. Either way it's going to be on both ends of the coil with epoxy and will also be used to support the coil too. What happens if there's capacitance between bottom of secondary and ground? Pictured is a disk from that material. I soldered a thin copper sheet to bridge both sides so they would be electrically common. Otherwise it will be a capacitor and I don't know what the possibilities are so I'm tossing it out there to see what other people think. Have fun! Patrick