"I guess I don't have a specific number of AH. But I'd like to be able to go 4-5 nights parked without dropping down so far that the refer starts to reset. I believe it needs min 9.75vdc to run on LP for the control circuits"
This may be part of your problem along with are they being fully charged. It seems you could get more life than that. I run four gp 27 in a string for a 48 volt pontoon boat and they are 2008, 2009, 2012 2015. They are charged to 15.2 volts all the time. 6 or 7 months out of the year they just sit with a battery minder and a timer.
Does your solar controller have adjustable voltage? If you go to something like a Trojan they suggest 14.8 v daily charge.
