Does the coroplast prevent the guinea pigs from knocking the grid walls down?
I was planning to just use grids and coroplast, but it seems like the grids can be knocked down easily even with connectors.
No, the grids cannot be knocked down as long as you connect the grids well to the connectors. It is sturdy.
Another option would to have the coroplast edges higher, probably 7-8 inches high would be a safe height so the piggies won't fall off or accidently fall off. So in that case, you wouldn't use grids.
I wanted to be able to lift the cage in order to clean the coroplast.
I don't find that nessesary. If you need to, the best way to do that is just slide the coroplast out from the inside. If your using connectors sometimes it can be very tricky taking it out through the bottom.
It's easy to just reach and spray it and wipe clean. That's what I do and if you need to vacuum or clean under the cage just slide the cage out of the way.
What happens if there is space between the coroplast edges and the cage?
I'm not sure exactly what your saying but I think I have an idea. Most sign shops cut the coroplast to the dimensions you give them. Some charge extra, some don't. But it's not much. You just need to measure the perimeter of the grids once put together and use those dimensions and tell them, and that will be how big your coroplast will be and should fit perfectly. And just in case you have a misunderstanding, the coroplast is placed in the grid on almost all C&C cages.
How high should the bedding go on the coroplast or should it just fit neatly?
It depends on what bedding you use. Most bedding's about 1-2 inches.
A newish popular bedding choice is using fleece. It works spectacularly, looks nice, comfy to little piggie feet, smells nice and very easy maintenance. And it's so clean!
Tell me if your interested and I'll give you more information
Do guinea pigs chew on the cable ties?
I use cable ties and no, Thunder does not chew on them at all, I don't think he even knows they're there. I don't know about other piggies though.