For the port I cut a hole in the baffle that the PVC fits tight and then run a bead of silcone around the front outside edge of the pipe . Then I push it into the hole I cut from the back . You will have to take out the speakers to do this . Then let it dry for a day and put it back together . That's how I did these and have done it for quite a few others .
That looks like 1/2" baltic birch or similar. This is a 33% weight savings over 3/4" old school construction. Kudos.
Ah alright so I will cut the port holes to the outer diameter of the PVC rather than the inner, so I can snuggly squeeze it in there. Sounds a lot easier than trying to have the butt end of the PVC up against wood. Thanks for the tip!
I suggest that you use a construction adhesive rather than silicone. Keep silicone away from electronic parts. it's not compatible (except for the types specifically formulated for electronics, which cures differently)
Well that's good to know . If I do build another cab with PVC ports I'll use PL plus and that would be the right stuff for the OP . Didn't know silicone was that harmful . PL comes in a caulking type tube so running a bead around the end of the pipe would work the same . Just be sure to wear gloves and be careful , PL doesn't come out of clothes very easy . Let it dry 24 hours .