one of my bigger challenges is the math involved in wiring together LEDs to work off the battery.
Dude. You're nuking this, making it way harder than it has to be.
what is "RTVing"?
RTVing = applying silicone RTV.
double stick tape in there scares the be-jesus out of me. with the holes in the covers its going to be really exposed to the rain and mess portland gets in the winter.
What about super glue or some sort of epoxy to mount the LED board/strip? To keep out water, again, I'd consider some sort of clear silicone. You could completely encase the LEDs and the leads from the mounting point all the way to the exit notch, sealing out the rain and mess and keeping your wires from getting eaten.
I think I would want the lights hooked up on a separate circuit to the battery with an inline switch so I can turn it on and off whenever I want, id like to put the key inline there too so I dont have strangers coming by and playing with the lights but that might not be so easy. I had not thought of the quick disconnect though, definitely necessary.
Again, if you run a relay off of something connected to the ignition switch, like the headlight, it'll only have power when the ignition is on. You could put a simple switch in-line after the relay allowing you to turn them on and off, but they would shut off when you turn off the key.