Rad support loom Q - Aus spec ae86

[NIZLAH]

Hey just need a little info to help me do some rewiring in my 86.

Just want to know what wires are found in the loom/convoluted tubing that is typically found running along the rad support to the stock battery/fuse box location in an aus spec Ae86.

(apart from the headlight wiring - I know that's there)

Also what amp rated wire do I need for the headlights?

Asking because I'm redoing this section of wiring and have a lot of loose mystery ends from when I pulled my old JDM 4age & loom out (fuse box and everything went with it)
Trying to work out what I will need and what I don't when I drop the 20v in (no doubt most of it will still be needed)

edit - and also what functions does the square/cube like plug (that sits on the firewall above/behind the engine) house?
if that makes sense, I think it is a 6 or so pin plug?? {around 20mm x 20mm in size & feeds through the firewall on the drivers side}

All help much appreciated.

Cheers
Niz