I was one of the authors of the first edition of CAP733, and am reasonably familiar with both UK and USA regulations.
Glad to help if I can, and I think I can see a way through, but could I ask - what's the purpose of the flight, and what is it (or class and MTOM if you don't want to be too specific).
Please don't PM me (the box is always full), but you can email me via PPrune, or I'll put this thread on subscribe so I'll see anything you post here.
G