On one cage I have plastic panels, called coroplast from HomeDepot that I cut to size. On the other I have a clear shower curtain cut to size and held taut to the cage with a super strong velcro. Both work really well.
Make sure you have a plan for drainage, it'll save you a headache later on.

I have a water tray from LLLReptile under one cage and a washing machine drainage pan under the other. I like the LLLReptile tray better, but they both work well. I have a fitting with a hose on each and drain the water into a 5 gallon bucket.
The Dragonstrand cages look really nice. If I was getting one, it'd probably be the breeder series cage. I like how it looks and that it has the solid sides.