Right! A bit of time without posting, but I have still made some progress. A few updates...
I got some strange looks from the neighbours but I got some initial lengths by laying out string on the car.
From there I made the schedule attached previously and a list of wires (and connectors, pins, electrical bits) to order. Wires arrived... I was fortunate that someone I know had some leftover 'sureseal' connectors from a previous project. These seem to be a better option than bullet connectors, but still 'retro' enough that they won't look out of place. The relays etc. come with associated plugs to keep it neat. I will need a load of 6mm spade connectors and some splices.
Using the schedule I cut and labelled every wire, including idents for numbering so if the label came off I could still work out where it went. The wires were grouped and routed based off my string measurements. Currently held together with electrical tape - the final deal will be held with waxed thread and the idents will be removed as I go.
If found a few wires that I'd calculated the lengths wrong for, so had to do another order, but got there in the end. Next step was to check my measurements on the car. I didn't want it to get dirty, so wrapped the whole thing in cling film and laid it over the car. Broadly speaking it was right, but there were a few minor issues:
- The length of the wires going from the bulkhead to the starter motor are too short by about 200mm - I'm not sure what's happened here, needs some investigation and potentially some new wires.
- Spacing between a few bits; I'd been a bit generous with the string, so some things need shuffling about - all easy - but particularly around the battery tray area where it was hard to get reliable measurements and so I've stacked up several generous tolerances. Better too much than too little.
Next step is to make the adjustments required, and then fit heatshrink to the harness before I add connectors. I'm not going to shrink the heatshrink until I've checked the function with as much of the electrical system as I can. My father in law has also ordered an autosparks loom so I will likely measure off against that as well.
More updates to follow, but potentially with a gap as there's lots of other work to do before the wiring becomes the limiting factor! At least now I've checked my measurements the bulkhead can come off...