I use my for the same reason, school presentations.
I have an Observation hive. (2 deep frame). It has overwintered well, but I still don't see it building up as I would expect so this year for a number of reasons.
There are pics at my website. A elder beekeeper in CT made the hive. I bought it for $69.00. PM me if you want his contact info, or I will give you my phone # and we can talk directly.
I have had it for a year, and mine did swarm in August, but that was my fault. To prevent the swarming, you will need to be able to take the bees from the observation hive to give a boost to one of your hives. but leave the queen behind.
They need to have access to outsite at all times, even in winter. the best position would be where they can get the warmth of the sun most of the time. Mine is on the north side of the house and it gets little sun, and the bees get a late start getting going in the AM to get nectar and pollen.
They will propolize all the vent holes, I'd let them do this and then you can clean them out in the spring. It should get a through cleaning every year especially hf there is a lot of burr/brace comb on the glass. The glass can get dirty. So to clean it, you want a place for the bees to go, so I use a nuc.