When it comes to the drying in the tube, I think sealer type has a lot to do with it. Shellac, tung oil, and quick dry poly's can form a skin overnight even in a sealed container. Watered down polycrylic might never skin over when sealed, just slowly thicken or separate.
I wonder if you could use a process like hydro dipping? Oil based clear(thinned heavily) on top or water in a 6" pipe and just dip shafts into it and hang them to dry.