I am getting ready to screw together another rack system. My question is this. I can't figure out how much spacing I need. Prior I used CDs as spacers on my previous rack. I used 1 CD on my first one, it now binds up a bit as drawers pull out. Then on a smaller rack I used 2 stacked CDs. Now I am considering using 3 stacked CDs as spacers, would that be enough to allow yearling colubrids and adults to escape? I know melamine racks sag with age and I want to allow for that but not allow escapes. This is rather frustrating and I would just buy a rack but I am on a severe budget and already have the wood cut and ready.