Depth of Perlite?

[cueball]

First how deep does the perlite need to be? Then I assume the plastic grid sits right on top of it (perhaps a pvc support under?) and the eggs on top of that?

I used ~3" of Perlite under the grate and only had to top off the water twice during incubation. The Perlite will support the grid, no need for any additional support. Good luck