hey jd.
i'm a little south of you, but mine have a fair amount of uncapped honey as well. the good thing is that there is lots of it. those boxes are nice and heavy with stores.
sounds like you are bascially overwintering a large nuc in a single deep with all drawn comb. this is what i would do, based on the experience i had last winter. i had five single deep hives, they were even smaller than yours.
first, find out how many pounds the hive weighs, and this will give you an idea of how many pounds of stores you are short. scaling up to 10 frames from my smaller nucs, i would probably shoot for about 70 lbs total for ten frames, (but ask locals what weight they would recommend).
michael palmer recommended to me to have at least half, and a little more than half don't hurt, in stores. the other half, or slightly less than half, should be left as open comb to help clustering.
so, find out if you need to feed in the first place, and then feed only as much as necessary to get to target.
while it's still warm, i would use 2:1, with 1000 mg vitamin c per gallon and nothing else added. when it gets so cold that the syrup stays cold all day, the feeder needs to come off.
after that, they are probably not going to starve for a long time, even if they are short. they really don't use a whole lot in the winter. you can weigh the hive from time to time to get an idea of how much they are using their stores.
i agree with insulation, it will make them have to work less and therefore use less stores. i like to make sure my top is insulated and ventilated just a little, to avoid any chance of the 'ceiling' of the hive getting cold enough for water to condense on it and dripping on the bees.
keep in mind, that syrup is not as nutritous as honey. it's like you or me trying to live all winter on soda pop. healthy gut chemistry of the bee depends on the nutrients in their honey. their immunity to disease is better if they get more than just sugar. that is why i would donate honey from another hive, but if i couldn't, i would use sugar to prevent starvation.
as far as feeding sugar when it's cold, what i found easiest was 10:1, (still using only vitamin c), which makes a damp paste that you can work into a patty or whatever you want. i put a 3 inch or so strip of plastic sheet around the top of the frames, leaving the middle open, and then put the paste on that. an empty super goes above the deep with the notched inner cover next, and then the insulated top.