I've read everything now...you can turn the internet off anytime.
Personally, I'd step out, don't see it as much etiquette, as I hate queuing.
Long stainless trough is pretty much the norm down here, although more uppity places have a row of individual basins, which is essentially the same.
There's a weird trough at work, which is sized to be a "two manner"...it's "cosy". Usual M.O. is stand central and adopt a wide stance, discouraging company...new entrants use the cubicles, or wait.
Once had a manager stride up behind me and say "move over, there's room enough for two", and shoulder in. Standing touching shoulders after being muscled in on is poor etiquette.
As to cubicles, if there are three in a room, males will very very rarely use the central...I've checked with the guys who fill up the paper, and it's true.