Ben,
I own a CUB SPACEMATIC which is no 5 years old, It is NOT an offroad Ct, but I have no complaints of it in that regard.
I did a trip last year to Karajini via the Meeka Rd, (boring) at Newman we left the bitumen and from then on it was rocks, rocks and more rocks.
Many vehicles were passed with blow outs or flats. The Cub was fitted with light truck tyres (8ply) and not a problem with them throughout the trip.
The stone guard copped a hammering though, and if I did it again, I'd fit something to the Towing vehicle to reduce the stones thrown at the CT.
Regards the stone guard on the camper, it's a CUB supplied and fitted and the plastic mesh is held on with electrical ties, which were to put it simply, demolished and needed replacing every day nearly. I went thru three packs of a 100 each. LOL.
The lpg tap and bayonet fitting also copped their fair share, and the tap nearly losy the red part coming loose from the hammering it received.
There are some stone chips on the paint work, only a close scrutiny would reveal, but IMHO for an non off road ct it came thru with flying colours.
Preparation is what it's all about, and if you prepare it well and keep an eye on your speed, the damage will be minimal if any at all.