suggestions on tracking changes, and ensuring progress is done in order?

[DadofThree]

Important items that I had to leave alone until later were marked many different ways:

Bold Sharpie Notes on the Aluminum, Painters Tape with Notes stuck to the free hanging wires, tags with notes zip tied to the car in the places that I needed to come back to, and Lists written on 8.5x11 and taped all over the garage.

The Bold Sharpie were good notes on aluminum, example "don't rivet back wall before trunk deck" or "Insulate Here"
Painters tape was a quick way to give big labels to wires that didn't have a location yet, example "Wire for Front Fans"
Zip ties and 2"x4" tags were good for hardware items, example "Not Torqued" or "locknut loose".
Lists were good for getting items out of my head and onto paper. Seeing things listed out helped out a lot. Dash items, electrical options desired, steps to getting it registered.

Don't be afraid to build it again if you know it's wrong or if you find out the order wasn't correct.

I've always said that I built mine 3 times; the wrong way, a better way, then the right way. It is well worth the assurance that you've done it right. Especially when you have passengers who you Love, and friends that trust you with their safety. Don't second guess anything by the time this build is done.