What are your power demands in the trailer? If you need more than 2,400 watts or so, I would suggest the 48 volt system with all 16 cells in series. The lower current at the higher voltage is more efficient. If 2,400 watts will cover your needs, you do get the advantage of having dual redundant batteries with two separate 8S units. You will need heavier cables in a few laces, but the charge controllers, fuses, switchgear, etc. is all a bit cheaper. Once you exceed 32 volts, you can't use the cheap ANL fuses anymore. Yes, you can push past 2,400 watts on 24 volts, but my thinking is 100 amps is getting a bit much. I would only go 12 volt if most of the loads are all 12 volt items, and the total power is always under 2,000 watts. 24 to 12 volt buck converters are cheap, efficient, and reliable now. Run the 24 volt around the trailer, and put a small converter where you need 12 volts. That way you can use smaller cheaper wire. Have the inverter close to the batteries, high current short distance again. At 12 volts, even the charge controller starts costing more as you need double the charging current of a 24 volt system.