Didnt read whole thread, but I noticed from past Videos "tilting" of UFO's
If anyone is doing UFO's (no doubt using the helicopter config)
Animate the WHOLE vehicle for the inverse of the source "horizonDive".
Done it before for the ArmA1 Osprey.
This makes it look like the UFO travels flat / horizontal, only limited pitching.
You may even want to try it for the "horizonBank".