so basically here is the design that I am following
you will have a lower base board mine will be a solid piece just to hold pvc inlet pipe and give the plenum a ridgid mounting surface
then I will have the plenum as pictured above that contains all the vacuum channels
then on top of that I will have a bleeder board glued to the top of the plenum and this will have about .100" skim off the top and bottom and your material will get sucked down through it because the mdf is actually really pour us
and carve away!