Used the 3/4 inch cabinet grade plywood. The light rack is 3 1x6 planks joined together though.
Ya I was being dumb toward the end of the night trying to get the cabinet hinges lined up right and still had the bulbs in the sockets from when when I tested it to see if they all worked, and managed to break one of the bulbs in half.
Skimmer gets here tomorrow, after I put it in the stand the tank will be ready to go back on the stand.