Yup, that was my understanding as well, that's why I only metioned dry paper.Do Not clean eggs for hatching. That removes the bloom which is very important for keeping bacteria out of the fetuses. Dirty eggs are fine. Never wash eggs for harching.
I talked also with some people locally and it seems that "stop overthinking it, the ducks knows" is the most sensible approach (while having an incubator available as a backup in case the ducks does know but does not care).