I am told you can use the extra availability any way you want - straight mileage booking, MFU, GUFT, AMEX 241. It's just once a year. You have access to A class, D class (not I, for Club), T class and V class. It doesn't have to be strictly on one PNR. So for 5 people, you can redeem 2 GUFTs, and for the 5th person use MFU. Ex-Eur is ok too (as long as the 241 is not involved).
I can see an ex-ARN trip to SYD for all of us in F on the horizon.
Nice.