SHORT DEPTH?
Setting the hitting at 2.8m-3.5m from the impact screen in the optimal range.
This depends on what type of projector throw you are setting up.
A short throw projector can let you stand closer to the screen, as you wont have a head shadow on the impact screen.
Short throw Projector 3.5m from screen
NARROW ROOM?
Narrow room with a low ceiling?
Go with the side set Projector at 5m back from screen.
It keeps the projector away from being hit by your swing, and keeps the head shadows out of a beautiful 5 iron into a back right flag.
Narrow room with low ceiling - 5m side mount projector