Helosammy - I know we don't operate to civilian performance categories but in the Sea King (Brit MilSAR) the assumption is that Max contingency power (30 secs) is what will be used as you are trying not to crash the aircraft and will use as much power as is available from the remaining engine.
Our Operating Data Manual allows us to calculate Min SELF (minimum single engine speed for level flight) based on that max con power.
We have the ability to practice all sorts of flyaway manoeuvres in the aircraft as we can select an engine into manual control, fix a sensible power to avoid exceeding limitations and then 'fail' the other engine.
The earlier conversations in this thread regarding 20 degrees nose down are probably based on the S61 RFM for worst case but are excessive for real world ops if the S61 flys anything like the Sea King - you trade far too much height off to get your speed at 20 degrees, the only time I would use that much is if I was hovering downwind. Our data is based on the actual aircraft performance and not simulations.
Our flyaway call is an assessment of the aircraft's ability to continue flight in the event on an engine failure - if you call flyaway with lots of tarmac ahead of you, the sensible thing would be to land - not an indication of intent by the pilot.