Greetings John and all,
I left mine 18 stored on my Trailex trailer for the winter. The trailer has "V-Bunks" up front and rollers in the back. I still need to build some 2' 2x8 bunks for the rear but I'm there yet. Anyways, to overcome the roller hull damage hazard, I bought a $4 children's swim noodle (fat kind), cut it into roller length pieces and then sliced the pieces open so they would wrap around the roller and provide extra padding. Works great, you can even double them up if so desired. FYI the same type of noodle can be used to wrap around the hull curvature (keels) for boats that are sitting on flat bunks. They're very spongy, moreso than the pipe insulation you find at Home Depot.
To me, perhaps the most important aspect to winterizing a Hobie in snow country is removing the tramp. In the short time I've owned my boat I've probably seen a close to two dozen beach cats blown over from the wind catching under their tramps (lots of unnecessary damage thanks to three big storms). I was on the beach during one storm and the difference between the tramp-stored and trampless-stored boats was remarkable. Suffice it to say, watching 350-400+ pound cats become weightless in the gusts is....well...."interesting".

Yeah, it'll cost you an hour or so in the spring re-stringing the doggone thing but there are several benefits to doing so: a. you won't have to worry about snow weight damage to your hulls, b. your boat isn't going to get damaged by blowing over and c. you'll extend the life of your expensive trampoline by not having it freeze/thaw all winter. My $.02. If I didn't have a trailer and storage box, I'd probably just rest the boat on four tires and anchor it into the sand.
As for venting the hulls, I left my covers off and plugs out for the month of October to dry everything out. Now I just have the plugs out so the hulls can breathe. They're bone dry even with the plugs out fulltime.