When you list placements of woofer and port, do you mean XYZ inches from the edge of the cabinet to the middle of the circle?

For the stiffening strips, this is how I read it:
Each panel (two sides, front and back) has a single 1.5" wide strip glued at ~12.06" (.06"? ) from the edge. The strip does not extend all the way from top to bottom (any suggestions on how far or is it cook's choice?). There are several randomly placed horizontal 'rings' that tie all four vertical strips to each other. The top and bottom each have a brace or two extending from front to back.

This one sentence still puzzles me after many readings:
"Shortening the tube to the 0.75" minimum should yield a ~T/S max flat alignment (max BW half space gain) once the horn is properly shelved, so none of this takes into account the LF wall/room gain." I understand that the room will affect the LF, but how does that relate to the first part of the sentence?

I plan to build three cabinets - the first from rough plywood to get a better idea of how to do it twice properly with nice the 13 ply Birch stuff. If you have patience for more questions, I have a number of woodworking posers for you.

As to whether I will "think it was worth the extra $$/effort," it damn well will be after I go through the palaver of building the cabinets! Just these will be quite a challenge for me, I'll save TL for another time.

GM, thank you for your many posts and patience. I'm looking forward to enjoying building these and doing some listening.