I have made this comment in various threads before, but I will do it again one last time. Car enthusiasts from the 60's continue to promote using wax, particularly Meguiares. What was great for your 62 Vette, is not necessarily best for your FG trailer that is 60 years newer.
Not only does wax products take a huge effort to apply and buff, wax by nature yellows with time and exposure to sunlight. I have seen some shiny waxed trailers that were as yellow as an old dog's teeth. That happens unless one takes a lot of effort to remove the old was before rubbing and rubbing more wax on.
Modern products, particularly those that have been designed for
fiberglass, and most for
fiberglass boats are much more appropriate, but yes that 62 Vette was
fiberglass, but there were no products made specifically for it.
My personal experience is that a a product called Starbrite boat polish (with PTFE = Teflon) works great, takes so much less work than wax, does not yellow, and has kept my 15-year-old Casita's fiberglass nice and white and shiny...and with little work (once a year at most for an hour or so -- no rubbing, just Wipe on and Wipe off. Your karate muscles will not be developed, however.
I suspect that there are other products that work as well, but I can't tell you what they are. I have no affiliation or self-interest in the company that makes Starbrite...