Kirk, the wrap I'm going to recommend is similar to the honeybeeworld design, however built more durable. http://www.inlandplastics.com/farmtarps/misc/
. Beemaid may even carry them. I've used them for over 10 years and they stand up quite well with minimal mouse damage (They chew the tarp, won't touch the insulation) and water drains out without harming the insulation.
Wintering bees on the Canadian prairies is a unique experience that has been improved tremendously since the border closure to mainland US bees. One big difference up here is you must
have a good top entrance (3/8" x 1 1/2") (preferably on the lid) and bottom entrance of at least the same area. Due to our extended period of below freezing temperatures, multiple months of moisture from the cluster will form as ice in the top brood box if this ventilation is not provided. If the colony is fortunate enough to have enough resources below the ice build up, the water will 'rain' down on the bees as the ice melts in early spring, making it difficult for the colony to maintain cluster temperature. The colony will likely die from starvation, or complications from getting wet in early spring. One operation here lost half of their colonies a few years back when a crew member closed the top entrances on half of the colonies.
Another good item for you would be the book "Beekeeping in Western Canada". Beemaid should carry it, and it has a wonderful section outlining both indoor and outdoor wintering, as well as many other relevant aspects, however it's disease section is dated. Good luck!