Dave, here is your design in action on a EQ Wedge
http://www.haven.k12.pa.us/orfft/wedge.html
Note the steep angle the DOB must sit on. Where as in a EQ Platform/Table the Dob is seted more parallel to the ground. why is this so, well you need to look at the following link to see the theory its got me warped.
http://www.atmsite.org/contrib/Shaw/platform/