I'm probably way too late, but whitewash dries rather quickly, whereas glaze retards the drying of the paint. Whitewash will begin to dry when you apply it to the wall and you won't have time to rag it all off.
Ragging off will require glazing, which is a transparent, slippery medium that you add paint to according to the directions on the container. Oil-based is easier, but toxic and requires solvents to clean up.