idg - thank you for the response. You're quite right that the FCOMs are often inadequate. Input from ADRs makes sense, but do you know any references for this? Would a partial failure of, say, ADR1 only affect the FPV on PFD1, thereby giving differing FPV indications on each side?
Interesting about the balance theory. Be careful what you do with the rudder when trying it out!
Regards
SWW