[pepianoman]

For the indication, you could put a small button in the upper right corner with a "P" on it.. Pressing the button would turn off performance mode. Pressing anywhere else would turn the page as it does now in performance mode. You could have optional ways to turn it on, such as long press, double tap, swipe, two finger long press, etc. The user would have to pick one action to turn on the overlay and a different action to turn on performance mode.

I would like to see a shortcut to annotations also without going through the overlay menu.. Other users may like a shortcut to another task. Maybe you could give several actions (long press, double tap, etc,) and let each one be assigned as a shortcut for a different task.