I've spent alot of time trying to create helo & helo v helo scenarios, so I will look at this with interest.
Since helos are seen as flying APCs they attract sh#t from more directions than anything. Also remember that 'trivial' damage can force you to retreat off-map in an otherwise working chopper...
Apaches are the best to use as the combination of fire-control and vision gives the most lethal effect.
Don't be in a hurry to move though, the tests I've run show that lurk, kill and run is the best tactic
