I was on the search to replicate the sound of my current SVS and I already had the amp and was given the port length info, box size, driver to use to get me really close. The construction part was up to me.

Side note, I had modeled this up years ago and came up with similar construction specs. I was using Win ISD software and sonosub software. I basically went for a box if instead of a tube and then just needed to make sure that it was tall enough for the 17" port and yet wide enough for the 12" woofer.

"Box" dimensions don't matter, it is volume, port size and length, woofer, and amp.
2-M60s, VP180, 8-M3s, SVS 20-39PCi, DIY Sub, 8-Shakers, JVC RS45, Anthem MRX-1120