As with the CP-19 that sits at my dock, the transformation away from the factory wiring started slowly and with additional consumables, well my word! This became a rats nest.
Enough ... take a few days, spend a few bucks, practice how to solder a wire to a crimped end ... and than ... put the crimped end into the bench vice and pull the wire until the wire parts but does not pull out of the end ... now your ready to start.
The dining room is a good place begin, and write down EVERY consumable on board your ship. Make that list. Make that diagram.
From the heavy amp draw Chartplotters and the stinking bulb illuminating the compass.
If you believe 18 gauge is good enough jump up the 16 gauge and if 16 gauge is thought to be good enough, jump up to 14 gauge ... get the idea?
Every end is tinned with acid free solder and inserted into an end of some sort, than soldered again after being crimped ... for my electric bilge pump under the port a potty
two 'more than adequate wire gauges' were fitted on to one end, crimped and soldered to the main fuse protected buss duct that I created on the bench ... way before being thoughtfully installed in just the perfect place.
A really neat trick is to take two lengths of wire and clamp them into the vice on the bench.. one red, one black. Run about 40 foot out for each length and take the other two ends in a drill motor and pull hard while the drill twists the wire. makes a very nice wire in which to wire all the components together.
Everything goes to a terminal and fuse block and only two heavy wires run to the battery. Now go wire your boat and change every bulb to an LED bulb. And those I solder. No relying on "holder" to keep the bulb in place and to supply a GOOD soldered ground directly to the bulb's contact point and the bulbs barrow.