Hi Salvo,
I have no choice but to have two banks--they are in different compartments.
The logical choice for the 24 volt would be the bank of four. But that bank uses copper pipe buss bars so it would require a rewire.
I'm a huge user of amp-hours and when I was part time I would rely on the bank to "get me through". Between trips the solar would return the banks to fully charged.
Now that I'm full time and it is winter, the solar is doing very little for me. So far I've not had to use the generator and I can heat down to -10 C on 3000 watts (two 15 amp shore power cords). But tomorrow night it is to go to -18c.