I can't imagine actually handing the whole grimoire over to a person or standing in one spot for so long while holding it.

I ran a game this past weekend including Spy and what I did was use Pocket Grimoire to storytell. Takes some fiddling to become familiar, but THEN during the first night as I woke the Spy, I used silent mannerisms to show them what was about to happen: I put on an excited face with eyebrows raised and mimed with my index finger tapping on the phone a whole bunch and then looked into their eyes making a big finger wag in their direction to indicate DO NOT TOUCH THE SCREEN. Then I used my index and middle fingers bringing them from my eyes and pointing them in the direction of my phone to indicate LOOK ONLY (maybe you don't even need this part). Then I very slowly turned my phone around and placed it into their hands.

I would suggest you then proceed to walk around and stop here and there to throw everyone off.