To make alignment to the screen easier, I used the free creo elements cad package to design an adjustable bracket and then printed out the parts. The images below show the results. It works a treat.
It adds stability to the projector as it is not mounted from two points on the bar and can quickly be adjusted if necessary by turning a thumb wheel to raise or lower it.
This is the design in the Creo Elements cad package.
This is the end result looking from the back of the projector. The bottom nut is a nylock nut that holds the threaded rod and in the top clamp section there is a standard nut in the thumb wheel adjuster with some washers top and bottom.