Last year was our first year as beeks and like yourself we were concerned about how to over winter our hives. We did a lot of research and found mixed feelings with using SBB's, wrapping with tar paper, etc. What we ended up doing was leaving the SBB's on all winter, reduced the entrance to the 3/4" opening (make sure the open is at the bottom so the bees can push out the dead), and did not wrap the hive.
To block any wind, we put up a snow fence with an old tarp over it. In our research, found that it wasn't so much the snow and cold that hurts the hive, but rather the cold air blowing up into the hive.
Our hives are also about 2' off the ground.
During last years winter we would check on them regularly and was suprised at the heat you feel coming out from around the telescoping cover. At the bottom of the hive there was never any snow. Just a square shaped patch of grass.
We had a mild winter last year and had 100% survival. We are going to the same things and hopefully have the same luck as before.