Great DIY and work, looks fantastic
. Game on for me now, It's the right price for my fixed income in retirement, I'm going for it.
If I may make one suggestion that I may have simply missed in reading through your write up that I learned the hard way early on in over 1.5 million miles of trucking primarily in the US rust belt, Canada and Arctic for 10 years....
For those that chose is to use crimp connectors vs solder and shrink wrap, especially if you it's your DD and you drive in the salt and snow all winter, prefferably use only the crimp connectors that have the shrink wrap built in. If using the regular crimp connectors shrink wrap them and/or seal them with with the liquid electrical tape.
In my experience, unsealed crimp connectors on smaller wire like 16 gauge and smaller last about 6 months to a year before they corrode and break off running in heavy salt and snow. Better to pay the extra couple $$$ now or you'll pay more later.