Just wondering if I could ask for some help on what size wood goes in the stake pockets for an EZ-Dumper dump insert. It is a couple years old. For the leaf box I plan on using for post on each side and two 4' x 8' sheet of PT plywood. I measured the opening as rough 1 1/2" by like 3 1/2".......any help and pictures are greatly appreciated as leaves are falling like crazy in new england. Thanks!