Can anyone with access to B777 manuals please find out the maximum fuel imbalance?
There's no quoted Limitation/"maximum" in the manuals (whilst gross imbalance obviously isn't desirable I suspect for certification purposes the aircraft would have to be controllable one wing tank full, the other wing tank empty (e.g.holed)).
Balancing, when called for, is performed as ALSM/the FCOM 2 describes.