Maybe you just need to fill them with epoxy or fiberglass resin. I would coat the inside before doing this with aluminum foil or something. just a thought.
I am hoping the vacuum metal chrome plating will protect against the elements.
(For sure the UV exposure) It will be a fair weather vehicle so exposure will be minimised but the long term durability is definitely a concern. Worse case scenario, if I can make these cheap enough, I'll change them out every few years.
