I built a pair of these for a friend a few years ago. He still loves them. They are pretty big and heavy so a local woodworker would be best to avoid shipping costs.
Internal bracing helps a lot, especially bracing front thin piece of wood between the drivers to the back panel. Killing panel resonance is always helpful too because the woofer plays up pretty high and the rear wave touches every panel. I like to use double layer of plywood+MDF glued together with green glue, plus corner and cross bracing. Front baffle size should remain as designed for the crossover integrity, but the box depth can increase if you need to maintain internal volume while using thicker walls.
The molded SEOS-12 horn throat is not perfectly round and has slightly rough edges. These flaws can be seen as a FR anomaly around 8kHz, but I could never hear it. It might be worth smoothing them out before mounting to the CD. Make sure the CD exit is perfectly concentric with the horn throat before tightening the bolts. Enjoy!!