+1 with holgs
it's a bit manic to start with as everyone is aiming for the same spot about 250m in - but that's pretty similar to any IM swim. by 750m you'll have space around you so it becomes much less of a battle.
in 2010 when we did it they suggested faster swimmers went to the left side, slower to the right. that gave the faster swimmers a straight run at the 250m buoy, so the slower ones could stream in behind. Ok - that was the theory but it still turned into a bunfight!!