I am however a little confused on how you find port length and its placement in the enclosure. How do you find the port length and the corrected port length both at the same time?
Pialign also says I should use a 3.5 inch port that is 10 inches long. The depth of the enclosure is only eleven inches.

Also, would I want to a psd2002 for the HF driver, and with which horn.

I would be very thankful if you could send me plans so I can see what right, and or horribly wrong.

One last thing on the Pi alignment theory paper. The page to find the dimensions of the folded horn and enclosure, are X Y and Z internal or external lengths.

Thanks for taking the time,

Josh Fitzpatrick