No winter shrinkwrap for our Beneteau 323; she had a well-designed cover with a sturdy aluminum frame, made by GencoMarine, the same company that made the dodger and bimini.
It had a zippered back door and vents front and sides. This cover would stay put through the winter even when others around her were ripped to shreds by the wind.
When you do something like installing a winter cover only once a year, it can be hard to remember the details from one year to the next. So I wrote them down while they were fresh. When we sold the boat, I sent the new owners an instruction manual for installing the winter cover. Here it is. If you have a Genco cover on a different boat, you may still find it useful.