I would get the self tapping screws, they're easier. They cut their own threads as you're putting them in. Just don't get them too long so they don't poke through into the cage. I think 1/2 inch screws would work, maybe 3/4. Measure the screw that came with it, and then you'll know for sure what length you need. I used self tappers to attach plastic chain to the top of my cage so I could set up branches without tying them to the screen, worked great.