In looking at the pics of the under dash area on Lee's car, I got to thinking about wiring. I know wiring has been mentioned here but just to bring it up again...

I removed any and all unnecessary wiring in my car but had to add some real heavy wiring for the battery in the trunk. I really tried to look and see where I could eliminate things that were not in use like the ash tray stuff, map light, rear defrost stuff, etc. I removed the unused wires and terminals from the junction block and fuse box, they were not cut out with the terminals left in place but removed intact.

You wonder if something like a Painless harness would weigh less? The factory harness has a lot of tape wrap, terminal connectors and associated bracketry to keep it in place. Even if a circuit is not used, the wiring is often left in place since it's tied in to the rest of the harness and can be a hassle to remove.

Just thinking out loud, not sure how much actual weight you'd save and whether it would be worth the effort/cost to change what's there now. Probably nothing close to pounds, more like a few ounces. If starting from scratch, I would think an aftermarket harness would be the way to go but retrofitting one into a currently working system would probably not be worth doing.

Also, using relays allows the use of narrower gauge wire.