Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
The Pyro requires micro attention about every 10 seconds. Like I said earlier, maybe all helis are like that. <end rant="">
Being a fictional aircraft as well, the FDE was up to the original designer who has answered some of his FAQs on the Pyro site. For your kind of flying, why not a proper bush plane?
You might try this in your .cfg file:
[helicopter]*
low_realism_stability_scale = 1.0, 1.0, 1.0
*See: https://msdn.microsoft.com/en-us/library/cc526949.aspx#mozTocId6418