Steve,
You don't have to pay attention to what lasttruck or I write, but you can save yourself a lot of grief here (and maybe some money too)..
For batteries, use GC2 series (anybody's bets 12V in parallel).
Get a real monitor like Trimetric, Xantrex or Victron.
Get a good converter charger that is smart, and three or four stage. Suppliers are Progressive Dynamics, Iota and (Iforgot).
Lead/Acid batteries do not like to play well in parallel.
A volt meter can tell you if you might be in trouble.
An amp meter can tell you what is happening right this moment only.
A real monitor will tell you if and when you might start to worry and a lot more.
This is the sort of thing on other people's expensive performance cruisers (read racing yachts put out to pasture) before the depression. I am trying to pass along other peoples costly lessons.
Matt