First Den Nobile's - Looking for advice.

[PuiPuiMolcar]

I have the exact two den nobile that OP have and I was wondering about that too, I still water them during winter just less and they bloomed for me just fine.
I dont know if this whole letting your dendrobium completely dry out is a thing with dedrobium densiflorum too because every single orchid shop that I have seen of that orchid have incredibly bone dry cane that just looks awfully close to death door.

[Roberta]

I learned the hard way about the "drying out" thing... when I first got into orchids, I heard "no water from Halloween to Valentines Day". Had several die. Reduced water may be useful for blooming, but unless you live in a humid environment that cools off at night to give lots of morning dew, don't do it! In nature they may not get rain but they do get that water. So don't fertilize in winter. But do water every couple of weeks at least. Last winter I didn't move my nobile-type Dens away from the sprinkler so they didn't dry out at all (but didn't get fertilized), and ended up with one of the best bloomings that I have had in years! So I'm convinced that temperature drop is more important than drying out. (They did experience what passes for winter in southern California)