From the short FRA experience, I'd do 70AB before 80AB because all of the aft cabin is at risk from galley noise.

Looking at the seat map in the wikipost, I think that there's also more risk of light disturbance from the toilets if in 80AB because they're positioned inboard; the toilets just ahead of 70AB are outboard so you can't see the door opening if sitting in 70AB. I hadn't noticed this when actually in the cabin, but the effect of similar layouts on other aircraft suggest that this is something to bear in mind here too.