Charlie Craven has a bit different take on the fly that makes it a lot easier (for me, at least) to get the proportions right:
http://www.charliesflyboxinc.com/fly...m?parentID=143

Tying the wing in first, it comes out right (almost) every time. Again, like Hans states, proportions are critical. Thread control/tension are important, too; push the thread close to the breaking point and you'll get a sturdy fly, don't and you'll have an unintentional "spinner". Try both methods and I think you'll be happy with the results.

Regards,
Scott