Just doubled the solar on our roof a month ago. After next season I will decide if I want to double it again.
In the process, I discovered that the original solar (installed by the dealer) was wired wrong. I bought the stuff to double the solar because I was getting insufficient charging. I discovered that I was getting NO charging, but already had the stuff to install the second panel. (The dealer had hooked both the positive and negative wires from the solar to the hot terminal of the battery. He also didn't install fuses. While in there, I added a disconnect switch between the solar panels and the solar controller.)
Bobbo and Lin
2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6
2017 Airstream Flying Cloud 23FB