Get a proper frame and a tarp. The shrinkwrap is wasteful and it's difficult to let the boat "breathe".
Some tips I've learned the hard way:
Get the tarp split into two pieces. One 35 foot chunk of waterproofed tarp is well over 100 lbs. and it is difficult to maneuver solo over the frames.
Leave some fenders out to leave an air gap between the hull and the tarp. It can get surprisingly warm in there (which makes deck work and even glassing possible...with ventilation...on cold days), and you don't want to trap condensation or to encourage mildew.
Either drop your stanchions or put tennis balls with a slit in them over their tops as anti-chafe...the wind WILL erode holes in the tarp if it touches anything metal.
Colour-code your frame "spine" and "legs" with electrical tape, number/letter code, or whatever you wish. A real time-saver if you only have a 90 minute window of wintry daylight in which to assemble the thing.
Bring a friend and two identical socket wrenches. After putting the spine in, put the largest set of legs (usually at the mid-point of the beam on, then work your way back.
Check the tarp periodically during the winter for ice-buildup, tears, or loosened ties. Visit the boat just to have a look around: I've had pleasant times under the tarp with pals who just want to hang out having a coffee with a shot in it on a cool...not cold...boat while the winter winds are howling outside. Of course, I run power to my boat all winter, because I like to leave the batteries in, so I can play the stereo!
Lastly, fold it carefully and stow the tarp OFF the floor (like on a rack or in the rafters) to keep it clean and free from mildew. Fold it dry. Lash the frames together in one bundle with short lengths of line or bungees, and you can fly it under the rafters of a garage for the summer.