I am considering permanently mounting 4 390W panels on top of a 7' x 16' Cargo trailer and 6 additional 390W panels (3 on each side of the trailer) that are deployed using gas-springs. Here is a link to a simulator: https://www.gasspringsshop.com/gas-spring-calculator/.
The side mounted panels...
I'm glad this fact came out. The NEC (National Electric Code) is heavily influenced by the NFPA (National Fire Prevention Association). Fire and electrocution risks are probably higher off grid, especially DIY systems. I know my first system was.
I was responding the last 6 words from the OPs reply. "if I wired everything in series"
24 volt array, 24 volt PWM SCC, 24 volt battery, 24 volt inverter. He just doubled the capacity of the system by adding 1 12 volt battery.