I use the trays...I make sure to have the protective cover boots over the Hot / POS. terminal.
Is it cheaper to purchase custom made cables or make your own.
Sure it will be more expensive to make the cables....This is due to the expense of the tools. But where are you going to get a 52in cable as a example?
They only make standard lengths. 12, 24, 36, 48in.
Buy the tool or find someone who has one.
As to the main switch panel......yes all the wiring can be replaced.
Here is a color code sheet.
http://www.marinewireandcable.com/p/mar ... codes.html
Now here's a hint..... Nav lighting is Gray.....But when you get ready to hook up the 3 wires to the switch....which one is which? Port get a ring of Red tape on each end.....STB gets a ring of Red on each end.....Anchor light gets White on each end.
If your boat aloows....you can hook the Green and Red together and bring one wire back to the switch....All layouts are different.