Another Ammeter bypass question:

Use a machine screw and self locking style nut. Yes on the heat shrink and maybe some tape. Putting them on the one terminal still exposes the system to a potential grounding issue.

I'm not a fan of the Mad approach on the rest of it. IMO, run the wire from alt to relay with fusible link and leave all the OEM wiring in place. If the bulkhead needs some fixing up, get that done as well. If bulkhead is in good shape, run it.