I've seen some pick up 5/8" baltic birch plywood that comes out closer to the real stuff (have not been able to find near me). I'm using 1/2" plywood and haven't had any issues with 1/2" screws poking through from below, but when mounting really thin stuff to the bottom I do have a supply of 7/16" screws as well. Any decent hardware store should have the 7/16", maybe even Lowes or HD. I think I did end up putting a thin washer spacer under my drop target mounts to get them to sit at the right height since the wood is thinner, easier to add spacers then take out wood.