Curtis
I was going to do that as well. What I ended up doing and it seems to work well was use one of my old doors from the side of the cabinet made from particle board as a baffel.
I cut out the center of the old top to just slightly smaller than the baffel. I mounted the baffel to the old top with angle brackets. I have about 1" below the baffel and 1.5" above the baffel. I mounted my test pressure pickup on top of the baffel about 4" to the left of the discharge hole in the aluminum top. It faces toward the front of the bench. It's mounted through an angle bracket at 90 degrees to the baffel and I threaded the back end of the tube and the hole in the bracket. I lock it in place with 2 nuts. Hose runs from the pickup on the baffel plate to the pickup inside the top plenum that connects to one side of the verticle manometer. The sides are 3 1/4" tall.