THat’s a real problem with a 50 amp controller and a 35’ RV if you want to parallel panels. Large voltage loss on a 12 volt system approaching 50 amps with all panel parallel. RV roofing has a lot of shading. Aside voltage loss if the insulation is rated at 60 C and 55 amps, why would I want to risk my wired getting hotter than that when roof temps are 135 - 155 F and then the wire goes down through conduit. 50 amps may raise the temp.
Sure there’s things you could do like get 90 C or 105 C rated wire, but I still want to avoid losses.
Some people don’t care about voltage losses. I do.
I'm with you there. There's only so much wattage I can put on the roof of my RV. Voltage loss is not something I take lightly at all.