If that were me, I too would put a sheet of plywood between stand and tank. I think it's generally good to have as much surface space to distribute the weight. For added protection, you mind as well paint it to match the color of stand and it would look nice underneath your stand as well.
EDIT: If you need to replumb some of your PVC, I'd suggest you add unions or union ball valves too. This way you can take apart most of the plumbing sections rather than cutting. You may have done that, but I didn't see any unions, hence just my .02.