After washing clean and labeling my tubers I dry them 6 to 8 hours before wrapping. Depends on how much humidity you are dealing with. I'm finishing up in a heated basement.

Let's see what others think.

Guess I'm more afraid of drying up than having them rot.

I dry mine overnight or 24 hours in the cold garage on a metal screen with newspaper underneath. Our humidity is very high, but just barely dry/damp to the touch will do. If you cut any big ones off, as you might want to do, let the cut ends dry over a bit. By the time I sort out the batches on the kitchen table, they are all dry and ready to go.

If they sit too long they will start to get just a little bit shrivelled- spritz them with a mist of water and cover with newspaper to rehydrate a bit, then sulphur dust (if you do that) and wrap.

One more thing: our local dahlia association says to dry in COOL air (says she who's used a blaring space heater next to tubers for several years to hasten drying in our damp climate LOL!) Once wrapped and ready to store, try to aim for 35-45 degrees and darkness for the winter.
Good luck!

I try to dig only as many dahlias as I can handle in one day. I dig, divide, add a fungicide, wrap and store within a few hours all in that day. You can let them dry overnight if you wish but I wouldn't advocate it and don't see any advantage to do so.

... and Bernie is one of our resident experts.

If I can do it in one day, I'll do so. If I have to wait until the next morning, after a night of drying, the next morning I will add the fungicide, wrap and store.

I had a friend who "did me a favour" and gave me a dahlia tuber ( like coals to Newcastle LOL), and let it dry for a week, cut off the neck ( and the eyes) and presented me with a nicely withered tuber not wrapped or anything. It is on the compost pile now. In return, I gave her a tuber with an eye, quickly dried, fungicided, and saran wrapped, along with a nice friendly smile. Of course, many questions persued. LOL That is how we learn.