PhotoReading upside down is great if you get distracted into reading.
I don't make the zoom too small. The brain has to work harder at processing the text. Keep using the technique and you'll find it gets second nature to stay in photofocus.
It's explained in both the course and the PhotoReading book. It's not necessary to see the blip page. If it disappears you have the x-technique to keep going.
Look through the book as if you have x-ray vision. It's a soft gaze. Bit like daydreaming.