Sorry, not used to new photo software or attaching images here. As you can see; "close shave" (i. e. tight fit)! This is the knock down box from PE (Denovo Audio; PE part no. 300-7076). I knew it was "quite narrow" for the SB29's. I have some 12 X 12 inch MDF panels and 12 X 12 inch high density cork panels. These will mount to the baffle board; MDF on baffle, cork in front of that. This gives the woofer extra distance/space off of the narrow baffle, allows for better mounting and provides a better seal and damping as the woofer frame compresses the cork slightly. Because the internal dimension is very close to the cut out diameter of the woofer; having the woofer "out" an extra 1 inch from the inside will help allow me to get more pad damping material on the walls the full depth of the box. I would normally never have a box width so narrow as compared to the driver size but as I said earlier; I no longer have a shop with lots of tools handy so I go with knock down boxes mostly these days and modify them to suit my needs.
I left one panel off when I glued up the rest of the box. I will make this a removable panel. I will add "cleats" (wood blocks) to the inside edge of all panels so I have a better and stronger fit for the remaining panel to screw into. When I glued this up; I also used fasteners. I used special point (self starting) screws that don't require a pilot hole to be drilled first. I used number 10 screws; I really wanted no. 8 or even no. 6 screws but couldn't find any in stock at the correct length with self start points. I chose flat head, "TORX" drive screws. No. 8 or no. 6 were not in stock with the torx flat head either. At first; screwing these in caused some splitting in the MDF. I increased the drill/driver torque setting, speed up the drill speed and "pushed" in with more force. This gave better results and stopped the splitting. I think this would have been much less of an issue with smaller diameter screws. These splits cause me no concern as there is plenty of adhesive (high quality wood glue) in the joints. I also added more adhesive at the joints as one would normally do with caulk and a caulking gun. So, a very tight and strong bond and seal; I am not worried about anything rattling or shaking loose.