This past year I had to halt my 7pi speakers build due to the unforeseen events we have all experienced. I have now all the parts and material in hand, ready to resume and hopefully complete the build in the coming weeks. Before preparing the plywood cut diagram I wanted to confirm if my understanding of the information you provided is correct.
Using the diagrams and information contained in the pdf file you provided, the internal dimensions of the bass bin should be: 16" W x 32 ¾" H x 7 ¾" D. The port opening should be: 6 ¼" W x 3 ½" and its depth 5 ¼" measured from the outside surface of the baffle. Is this correct?
Sorry if it sounds redundant.