Whilst not able to weight into the A or D class discussion my sister made an interesting discovery when calling about Y seats on the A380 on LAX-MEL.
She is a PG and we decided that 71D would be the best seat in the house to try for as there is no 70D. The word from QF is that 71D is not available for pre-selection as it is reserved for disable persons.
Alternately we got her into 80A which whilst being way down the back still has plenty of apparent leg room.
Feed back to follow when possible.