Sailed one on charter about 25 years ago (Aug 1978). If my memory serves me correctly, she sailed quite well but had been poorly maintained. The only feature I can remember clearly was that she had bottom-action winches, and that they were handed so that the starboard one went clockwise and the port anticlock.
I have a couple of sheets of info (TIF file) on the Wing 30 that I acquired when I bought my Wing 25. Send me a PM with your email address and I will forward them on.
Andy