Hey Tom,
I've got the same boresighter.
Here is my rough way of getting on paper with it.
It's about 25 feet down my hallway from my living room. I put the rifle in a rest on a fold out TV tray type deal and put the crosshairs at the top of the doorknob on the closet door at the opposite end of the hallway. I then put the laser dot at the bottom of that doorknob or about 2" below the crosshair.
This gets me close elevation wise at 100yds with both .30-06 and .243 win. It gets the windage near dead on.
Take care,
Tom