I have hived 3 swarms and each has filled up a single deep quite nicely in the last month or two. I haven't had good luck overwintering single boxes in the past, maybe less than half have made it.
I've wrapped, stacking singles in pairs for shared warmth and insulation. Not sure what went wrong.
Any other tricks? These are nice strains of bees that I would like to have around next year. And... I'd rather not combine as all of the other hives have two full deeps, I feel three is overkill. All young queens worth keeping.