I think that one reason for not running the chuck "empty" is that the jaws might make an unplanned exit. This happened to a friend who was testing a setup for rapid reverse for screwcutting; one jaw flew out and, amazingly, he had time to catch it and utter some workshop Esperanto.
Are you going to use coolant? If so, you might find that it makes its way past the grease under those raising blocks. More height can, of course, be gained by blocking up the feet.
Plus one for the book recommendations; depending on your taste, George Thomas Workshop Manual might also be a useful addition.