Our average has got to be -20 celcius to -30 celcius for about 4 months
Surely you should be better ask for local beekeeper.
Average temperature -20 celcius to -30 celcius for about 4 months ?
Are you sure! We have not that kind of values even In Lapland.
But it seems to be http://www.cpc.ncep.noaa.gov/products/global_monitoring/temperature/tn71078_1yr.gif
I've designed a lid with insulation built into it that will stay on all year round, 2-3/4 inch wood covers
That kind of wooden cover is really heavy to handle.
We have now stryrofoam hives which have relly good insulation values.
More than for winter insulation hive needs during spring upp to summer when they start brood raising.
In Northern Finland where they have -20 celcius to -30 celcius wintering in some kind of shelter is usual. One man puts his hives iside a hut which have made from insutating boad and he put "frost guard" heater inside. It connet electrict heating on when temperature goes under +5C.
Wintering under snow is usual.
And that feeding hole? You just need finger tip size hole in the upper part of hive that moisture comes out from hive.
You should accustome with some local beekeepers and learn from them how to handle hives in your area. By that you have a good reason to get new friends.