I've had excellent results using American Autowire, whether a '53 Ford F250 12V & alternator conversion, or LS1 swaps into FJ40s and a Jeep TJ.
For the specific OEM connectors, I generally can find them or fab them.
Uninsulated terminals with shrink tubing work well & look proper, too, in certain areas.
OEM-correct plastic terminal "covers" (like horn wires & etc have) & such are out there.