Rough math ...

cam bore of approx. 2.5" (I think I'm overestimating big time here)
assume max lobe size so radius from cam center to tip of lobe = 1.25"
pi x R squared = 5" dia.
5" / 360 degrees = .014" per degree
cam turns at 1/2 crank speed so 10 crank degrees = 5 cam degrees
5 x .014 = .070"

I don't think you would see much movement on the dial indicator for less than .070" of rotation at max lift - particularly on a roller cam.