Awesome. Thats the same thing I did to balance mine, except I cut out the bottom covering so I could glue in a mount to strap the pack to. I got some H9 covering to match and then sealed the opening. My FG-11, though smaller, once the module is added probably weighs in the same as your FA-72, so perfect match. What prop are you running? I put an APC on mine, but dont remember the diameter or pitch. Can't wait until June to see how many show up at the fly in.