Bill Tindall, E.Tn.
Sounds like spraying a waterborne has to be done with more care to avoid runs, than is the case with a solvent based paint. Solvent based finish can be sprayed at higher viscosity because it takes less energy to atomize the solvent. And, a combination of faster solvent drying and the large viscosity response of solvent finishes to solvent evaporation (because they are dissolved polymers), the applied film will quickly have much higher viscosity that the material being sprayed.
I have never sprayed a waterborne. What are the advantages of spraying water borne paint(or varnish) vs a solvent based paint?