arceye: So in answer to my question is yes!! we do have control over the heli headspeed but ONLY if we do NOT follow any guide to the letter on setup of pitch and throttle curves. If however we do follow guides of 50% throttle +5 degrees pitch and a well tuned engine the these parameters are what dictate the resulting headspeed and the pilot has no control over what the resulting headspeed is untill they fine tune the pitch and throttle curves.
POWER/LOAD=RPM. POWER=RPM * TORQUE. LOAD=DRAG ... varying due to rotor angle of attack (pitch angle).
Guides are for getting your heli in the air. What happens after that is up to the heli owner. All manufacturers give settings that will nominally get your heli flying.
Regardless of the settings you choose, everything still has to obey the laws of physics. IE you have to produce a force equal to and opposite of the affects of gravity in order to hover. You can set the variables anywhere you want but to maintain hover, the final physics equation must be balanced or it won't hover. Operating a Heli is a precise balancing act done with high energy variables.
So when you say a pilot has no control over the settings ... that's like saying the pilot has no control over changing the laws of physics. In that sense ... yes we are all confined to the rules of physics (or at least the result of physics equations). Fortunately, these "rules" have lots of variables that can be manipulated as long as the final equation comes out balanced. A heli is probably the best device to make use of the most variables all at the same time.
Good Luck,
d.tipton