Join Date: Jan 2002
Location: Vinson Massif, Antarctica
I would go with as narrow of a mesh as you can get. They will rub their noses on it, and if they have a larger hole that they can get a part of their nose or face through, they'll end up rubbing the fur off their face and maybe even irritating the skin.
I've never used FRP, but I have used pre-made counter tops as the floor of most of my homemade cages. They will chew up anything that is soft enough to get their teeth into, even if it seems like a flat wall. Make sure whatever adhesive you use to stick it on with has plenty of time to ventilate and dry. Any edge they can get their teeth on will be chewed up. So design with that in mind.
I've never found a particularity good mix of commercially purchasable soil/sand for a dig box... something organic mixed with play sand. Avoid anything with a fertilizer or mulch in it. You want an actual sandy soil, something more intended for fill, instead of something intended as a potting or plant mix. You don't want anything with too much organic material in it that is going to rot, collect bacteria and fungus, and stink.
She sits in her corner, singing herself to sleep.
Wrapped in all of the promises, that no one seems to keep.