Hello Troels,
I hope you are well. Here is write up for your builders response:
Firstly, thanks again for designing another great speaker (sub).  The 10" sub is finished and adding extra depth to my already wonderful Ekta mkIIs.
I have thoroughly enjoyed the build and certainly set myself a challenge with the cabinet design.  The cabinet is a lamination of 18 layers of 24mm birch ply.  I knew this would be a time consuming and slightly wasteful, although I have a plan for the offcuts!  I spent quite a lot of time creating accurate patterns from which to rout the parts.  The main pattern has interchangeable parts so I could rout the braces and Hypex housing sections.  The walls are 25mm thick and the bracing makes the finished subwoofer rock solid and pretty heavy (about 27kg).  I used short dowels during the glue up - these are placed at the intersection between all of the horizontal and vertical braces.  This should ensure a good structural integration and increase rigidity.  I realised (from the manual) that the Hypex module should not be placed upside down for ventilation and cooling reasons.  I contacted the technical support at Hypex and they were extremely helpful and advised that it would be OK if I could provide adequate ventilation to allow heat escape from the top of the chamber.  I routed large slots and these work well at allowing heat to escape.
The front baffle (48mm thick) is inlaid with a smoked Chestnut veneer.  I chose a dark veneer to allow the main driver to blend in (higher WAF!).
I'm not sure if the sub is completely broken in, but it is already adding extra depth to my music and giving a warmer and fuller quality to the midrange and treble.  It goes deep and far outperforms the 2 x REL subs it replaces.  I eventually plan to reuse the patterns and make a second matching one!
Here is a link to folder with build images:
https://photos.app.goo.gl/B51kA8nmEaJ4VYpt7
Thanks again
Jason

Watch all images from link above!