I don't expect 'officially opened' will make much difference, as QF would already be directing F and other lounge-eligible passengers to the new lounge.
QF says seating capacity is 240 pax but clearly this is being hammered in the evening peak, when you have QF2 arriving at 6pm so there's an offload of transit passengers, as well as people flying out on (and connecting from QF2 onto) the QF flights to SYD, MEL, BNE and PER, which all leave between 7pm and 8.30pm, and of course those flying ex-SIN on one of those flights will be in the lounge prob two hours ahead of time.
So count on 5pm - 8pm being a bit of a bell-shaped curve of capacity, and the peak of this really pushes things. It's also an interesting metric on how many WP and P1s there are!