Dale: Gee man! You don't have enough to do! I have heard this about retired people.
You may find a coating to apply to the cap, wires and coil but consider this. The wires are modern silicone rubber which already has excellent dielectric strength. This type of insulation also has the ability to prevent tracking, which is the breakdown of the surface of the insulation. However, in order to maintain this characteristic the wires need to be kept clean and dry. Theoretically, ultra clean water has great dielectric strength. This deteriorates quickly as minerals dissolve in the water and rain has all kinds of junk in it. The same goes for the coil top insulator and the distributor cap. Any deposits on them will cause tracking and a severe reduction of voltage at the plug gaps. In fact there may not be enough voltage to fire the gap. That's why your engine will stall. So, even if you found some magical stuff to spray on the wires, etc. the effect is temporary. What would I do? Nothing but keep the wires, cap and coil clean and dry. if you run through a deep puddle and the engine stumbles, pull over, shut down, dry the wires, cap and coil and Bob's your uncle. My 2 cents.