Whatever route you chose, because it is essential the the surfaces including those inside the chassis are completely dry before application, unless you or the company have access to a warm air drying facility, you might want to wait until next spring.
I'm in the same position as you and am considering the Dinotrol process by Flatdog. I've not seen any views on them either way, but at least I would get an excuse to look at their expedition racks and the Howling Moon roof tent.