[Th!rdeye]

Well from what i see, the fuel tank issue doesn't really effect the mustang. So i cannot make the Aft tank drain first, but i do not think it would make a difference the way the game FM is modelled.

Correct, Il2 doesn't model the CG shift for the FM - it only calculates the _weight_ changes.

Actually it does model CG shift. When you put flaps and/or gear down, it has a value for CG shift.