If you look at the pic you'll see at the end closest to camera looks as if the crossmember is lower than the others and it is uneven in a few places. My intuition tells me to get another piece of mdf and put on top and surface it to make it all level but i intend to have a vacumn table and im not sure the feins would pull enough thru 3 sheets of mdf. My thought was to take another sheet of plywood on top of what you see there, run the pvc thru the bottom ply and 1st mdf and attach collar for pvc to the 2nd plywood. That then acts like the bottom of the normal setup and you are only sucking thru plenum and top mdf. So it would be a sandwich (from bottom) of 3/4 ply, 3/4 mdf, 1/2 (or 3/4) ply, mdffor plenum, mdf for spoilboard. Will that solve my problem or do i need to go to the trouble of removing ply and mdf and shimming crossmembers instead? In case you're wondering the outside C rails seem to be level and flat so its the crossmembers. HELP!!! sufferin suckatash...this is frusteratin!

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