So, the reason I was thinking close in is DOF is much narrower. At far distances, once you are past infinity, all is good ( now maybe moving the screen does pass through a sweet spot that is obvious ). The second issue I see is how do I make sure the screen is square with the focal plane? I will give this some thought ( might work to start square ( adjustment agoinst the stops then turn each screw the same ), I like the idea of having a direct view of what I'm doing on the actual camera I'm trying to adjust.
Close in does not verify infinity focus. You make sure the screen is square with the focal plane by placing the screen on the film rails. Good luck.