I did a lot of boat work before the depression and used a lot of Amp/Tyco round plastic connectors. Not cheap, but infinitely more reliable than a 12V mousehole. A pair of 4 wire with two each GOLD pins ended up at about 15$. I would always buy enough for the job so I could set every the owner had and give him a couple more with red/black already fit.
Order from Mounser or Jameco. You have to order all the parts separately, plug chassis mount, back shell and pins (male and female). Once you do, you will never want a mousehole set again.
Matt
