You can adjust your screen settings at the following location
C: - program filesx86 - Foresight Sports Experience Components - Simulator set up tool (right click and run as administrator)
If you enter the measurements it will move the line for you.
To be in the centre you would enter 1.5 feet in the DX Field
For a Side Hitting mat the normal number that works is 4'
If you find the number requires tweaking you can re adjust by changing that number.