Mark,
Try (ABBC) A Better Bounce Card, you may like it better than the wink flash. It really extends the range of bounce flash, gives more exposure to the background, and great highlights to the eyes. Most of all it removes almost all of those bad shadows. It is cheap and works great.
I have done extensive testing with it original 580, and the results are that the ABBC is all I now use for bounce flash. My initial testing with the 580 II in EM mode using the ABBC shows even greater improvements.
But to get all the stuff on it, you'll have to put up with the inventors wordy videos at
ABetterBounceCard.com
Just suffer through them and give it a try.
Good Luck!
Wil