Hi, i have the 1502 sportsman and i use it to hatch eggs 1 time and not in a cycle. So basically i place 300 eggs every 21 days. I need to make hatcher trays for the first 3 racks because it doesnt have any. I was think of using aluminum, but does the bottom of the tray need to be wire or can it be a solid aluminum tray. How should it be designed?