So I cut out a battery box for the Zii... After checking with Andreas, I trimmed the foam on the indentations of the front box at the front and back edges. White PU for attachment. I set the front and back boards of the box such that they would transfer shock along the side and bottom boards. I routed out some battery strap slots (the middle one by hand, in case you can't tell).
Initial box cut, a little bit tall. I whittled it down with a fresh-bladed box cutter.
Not too bad. Fits snugly in the slot.
Oh no!! It's just a bit too narrow for the 3S 3000's! It's pushing one side out... That will affect the structural integrity in a crash, so I may recut the box.
Here's the batteries snugged in and tied down. Will talk to Andreas about the best place to put the APM, receiver, and ESC.