Temporary upgrade to a 12v off-grid system

I'll likely to start building my off-grid house early next year which will require a brand new system, but in the next few months I expect to be shifting to working off-grid in my 5ver for at least the next year. As such, I'll need to upgrade my system to accommodate my electronics and a split unit A/C. Most of my heavy use is during the day, but I'd like to have the batteries well charged up heading into the evening so the wife can watch TV without running the gen.

Here's what I have now: 300 watts of panels, a Blue Sky controller rated for 25 amps at 12 volts, 4 6v Sam's Club golf cart batteries, a Trimetric 2020 and a Xantrex ProWatt XW.

With most of my heavy use during the day and with the batteries already 2 years old, I'd prefer to not add to the bank. I'll run a Champion 4 stroke 1200w generator as a crutch on cloudy days or as needed. Gas in Belize is currently at US$6/gallon though, so I want to plus up my PV array. None of the components will be common on the new house, as I'll be looking at a 48v system likely with a Flexpower 2. I'd like to limit the cost of my temporary upgrades.

I'd like to add 300w of panels and enough charge controller to carry the full load. The new panels will have roughly the same specs as the old (Vmp ect). Should I combine the array into one big array feeding a larger controller (ie a Xantrex C60) or keep them split and add an additional charge controller (ie a Xantrex C35)? Is it safe to run 2 charge controllers in parallel to the same bank?

Thanks!