Just done a return trip to DXB booked into WT+. Cabin was totally full both ways, and I was offered online upgrades at check-in both ways, both at £659. On the way out asked in T5 airside to upgrade, was told the available seats in CW were 'flashing red and blocked for staff'. On the way back delayed check-in as late as possible hoping for op-up. Still got the offer a couple of hours before the flight. Asked at the gate and was told nothing available.

So doesn't answer your question fully but you now have a recent online check-in (ceiling) price as well as the fact that the DXB flights seem to be very busy at the moment.

I should add that both WT+ and CW cabin on the way out was heaving with staff – most of whom spent the flight saying hello to each other and the cabin crew, moving seats for various reasons (non-functional IFE mostly), and either changing out of uniform or into it (with one unfortunate CC then asked to help secure pax for landing at DXB).