So far with mine, it feels like fingertip size is about the smallest 'eye target' I can use for a close-up screen (think roughly the position of a held iPad) an

So far with mine, it feels like fingertip size is about the smallest 'eye target' I can use for a close-up screen (think roughly the position of a held iPad) and still have 100% accuracy. I would bet that the limits of eye accuracy are the math basis of window resizing with push/pull movement, so that the accuracy rate remains the same for farther-away virtual screens.