jen, i don't know that you need 2 inches of insulation under the tele cover? maybe like scott said somewhere, an inch or so?
like jack said you can over insulate a hive.
i use an upper entrance, other's don't. i do think for me this allows extra moisture out, and on warmer days allows for the bees to take cleansing flights when the bottom is clogged with dead bees or ice/snow. i wrap, for two reasons; for any solar properties and as a windbreak. there were many years i didn't and found that my bees seemed to winter better with a wrap on. i have tried all sorts of contraptions underneath the outer cover, even wood shavings as pete mentioned. straw, hay, and homasote. in my opinion homasote can be a death sentence. it soaks up extra moisture for sure, but sometimes it gets so soaked, freezes, and thaws and rains all that moisture back down on the bees. i started using two inches of the pink stuff underneath. for two reasons; i think it blocks any extra ventilation, and also heat rises from the cluster (excellent description on condensation pete), so less loss of heat; and to maintain a warm ceiling so that moisture from respiration doesn't condense on the inner cover and fall back down on the bees as pete said. i don't think the insulation provides any great deal of 'insulation' to keep the hive/cluster warm itself.