The holes in the center are pretty big, probably about 3/4" or more, if the water gets to them then the water has no problem going through, it's just getting the water to flow to the center that i'm struggling with. I might hit up my local Tap Plastics and make some kind of platform that ramps down to the center from all four edges.
I've got a whole mess of screen I can use for the bottom, I just want to get the holes working before I put on the screen.