Re: on board charger question
First, to answer bama's question. There are several good manufacturers out there. We use ProMariner at Proline, I like them a lot, but some will disagree here. Many here use Guest, which we used to use, and a lot of people like them. Minn Kota makes a good charger. But almost all of todays chargers don't really care what type of battery you have, be it lead-acid, AGM, or Gel Cell. However, Gel cells require lower input voltages, the good chargers will allow you to set them for gel cells.
Now capndan, I personally would go with a 3-bank, rather than a 2 and 1. You can extend the leads up to about 25' using 10GA wire, just remember to keep the in-line fuse holders at the ring terminal ends in place when you splice that end back on to your extension. I've been doing this for years at the OEM builder level with Guests, ProMariners, Charles, Xantrex chargers, never a problem. One thing you might want to use to make your install a lot neater is one of these...
...made by ProMariner, where you don't have to cut the plug off, or one of these...
...made by Marinco, which gets hardwired. Either way, you can mount it in an obscure location, it gets rid of a bunch of coiled up wire, simply plug your extension cord into it and you're good to go...