I think I may have a similar situation with my 2017 Arctic Fox 27-5L which would have the same roof space as yours, and have a single 15k air conditioner with soft start. Goal is to be able to run the air conditioner when needed (mostly on East Coast) and computer equipment (two laptops and two...
I have allocated space for a 3rd SOK battery and have a 2200W Honda portable generator as I understand even 1200W solar would not be able to charge a 618Ah battery bank in a single day.