You've got mail! ;-)

You wrote:
>That's right. PiAlign recommends a 3.85 ft3 motor chamber tuned to 37.5Hz
>with a 4.65" dia. x 4.4" long port, or a rectangular port that's 3.1" x 5.5" height
>and width and 4.4" long.

Okay, 3.85 is a touch bigger than the Pi4 Pro, but that's considering external dimensions, as if the walls had no thickness, and the 1602 occupied no space at all. Hmmmm . . . How do I ramp up the externals to get 3.85 internal using 3/4 stock with a doubled baffle?

In terms of proportions, I'd like to have 29"-30" height and 17" width to get Bill's horns to the right height for seated listening (spkrs on short stands), and match the horn width.

If I take the Pi4 Pro cab, and arbitrarily bump each dimension up .75" for illustrative purposes, I'd have 26.75"x18.75"x14.75" or about 7,400 in3 or 4.3 ft3 externally. Reshaping this, maintaining the volume, I'd have 30"hx17"wx14.5d.

I'll want to hit the volume more precisely, which will change the dimensions, but will those sort of proportions keep me out of trouble? Is the height too close to being an even multiple of the depth?

This is getting exciting - Diverse drivers rolling along in brown trucks all over the country . . ! ;-)
Keep your ears and your mind open.