I don't hydrate the nest for the camponotus at all. I keep C. vicinus in ants canada vertical omninest.
I don't see any ants spitting water in the nest. They seem to know to hydrate it and are doing well.
I have a heat lamp I put on the side of the nest, not that close either. They seem to move their eggs away from it and don't like the heat as much as the novomessor cockerelli.
I just put the whole nest for camponotus in the fridge.
My 20 gallon formicaria can't fit in the fridge, so I keep novomessor cockerelli and honeypots (coming soon) which don't need hibernation.