wow good info on that site. your really going to have to know how much amprage each item uses if your looking to staying with smaller guage wire to keep boat lighter. if you dont care about wieght over kill is the best policy
***** remember with no frame grounding you need to put in ground wire length into consideration******** if your running amps for stereo like me im running large guage power and ground so all my dash power is pulled from there. using realys is great way to down size wiring, you can get relay packs from colhersy keeps every thing neat and tidy. just rember draw it out. plan your roughting and put in jump point incase you get stuck out in the water. ie. at you wire lug point on the motor put power , ing, and start side by side will help you in a bind.
wiring is all smoke and mirrors when you let the smoke out the mirrors dont work.