What are your needs? 12 volt or 24 volt. The 12 volt and 24 volt configurations store exactly the same amount of energy.12 volt, more off the self small stuff to run. 24 volt, less voltage drop, smaller cables, more efficient use of charge controller (2x more solar panels at 24 volt battery bank).12 volt bank needs heavier cables, has more issues with voltage drop in cables.-BillPS, what is the AH of the cells?
Then there is no choice. With 12x2v cells, you will have a single series string of ~700ah @ 24v. There is no parallel option.