Confident enough? Does that ever happen?
Start a few nucs in the spring, its too late to start now...
The nucs will give you a reason to get into them more often. You need to manage them more aggressively than you do a hive.. they will expand quickly, and need to have frames of capped brood pulled... put those frames in your other hives that need the boost, and swap in frames from that hive that are drawn...
With the nuc, you always have a queen if you need one, you can strengthen weaker hives with frames of brood. Nucs usually draw WORKER comb rather than drone comb.
The trick, if you wish to overwinter them, is to make sure they are strong, without swarming.. I usually stop pulling resources from nucs about the end of August and let them build up. They are less likely to swarm once it starts to cool down.. feed if they need it so they have the top box filled with capped syrup or honey.. Come October, Insulate the top, wrap with tar paper... Put sugar or winter patties on top of the top bars, and walk away until spring.
I have had about equal luck wintering nucs WITH an upper entrance as I have without the top entrance... Hives I have always had better luck WITH a top entrance...
Overwintered nucs command a PREMIUM price if sold the following spring.. they are poised to EXPLODE with bees... If you lose a hive or two over the winter, the nuc that survived will replace your main hive losses instantly...
Nucs are GREAT to always have available!