Bit of inspiration (??):
http://members.optusnet.com.au/~jano...mydobmount.jpg
I also have a short flat base for the Dob box, which is perfect for kids under 10 yo.
But I should have used thinner plywood. I chose the materials on a general principle of engineering: if you are unsure and can't be bothered, make it strong enough to take 10x the load.