Hello Shadow,
I haven't been that far South on the Atlantic for a while, so I was unaware of this trial.
Many of us that operate in Africa apply our own 1 or 2 mile right deviation due to the poor standards of ATC in the region, but that is less of a concern on the Atlantic with CPDL and the like coming into fashion. Also, Africa is as yet non-RVSM.
One point comes to mind though, suppose the A380 (or even a smaller aircraft like the 767 for that matter) was flying Eastward offset right two miles and a B757 was Westbound also offset two miles right and 1000 feet below the A380's level. If there was a wind of sufficient strength from the South, it could still effect the 757, in fact, it could be detrimental to fly offsets while flying opposing tracks for this reason.
It is well know that wake turbulence sinks and fans outwards behind the developing aircraft and that it also drifts with wind effect. So, my concern in this environment would be just who would be delegating (or recommending) which offset to use, if any.
I would say that if the upwind (crosswind that is) aircraft is higher on opposite tracks, it is better to have both aircraft fly center line, whereas same direction traffic would be better having the higher aircraft offset right for a wind from the left and the lower aircraft offset right for a wind from the right.
Of course, this has to be managed continuously on the NAT tracks, preferably by the crews themselves - IMHO, which is exactly what the NY Oceanic ATC are recommending. I had a rule of thumb on the Atlantic for same direction traffic, for every 0.01 mach difference and each 1000 feet allow 20 minutes for likely wake turbulence conflict (I personally liked precautionary seat belt sign usage). So e.g. an aircraft 2000 feet above and 0.02 mach faster could likely cause problems for a lower aircraft forty minutes after passing overhead.
You can probably tell that I have absolutly nothing better to do with my time than write stupid posts like this.
