There is no one answer fits all. Just like there is no one perfect car or house for each person.
General it seems to me that most questions come from a lack of belief or faith in the system. If you knew it was going to work for you, what would you do? Why are all these questions important to you?
I was just wondering how much should I photoread?
How Many different books a day should I photoread?
To answer them, it's pretty simple I think. As many as you can. Forget that it is PhotoReading. What if it was learning to ride a bike. How many times would you ride to become a successful rider?
Should I just stick to one at a time? If I do photoread a lot just for practice is it necessary to activate all of the books?
You can PR as many books as you want to. No you don't have to activate all of them fully and systematically. You could activate them in others ways I find, i.e. If you're reading cooking, cooking is a physical skills, that's where the activation comes into play. By doing the physical skill.
If I photoread a book can i also read it normally for pleasure reading?
Yes
Should I photoread a book only once a day or should I photoread the same book multiple times (how much of a difference will it make?)?
This isn't something I've done personally. If I know I'm going to do lots of "book" activation, I PR it multiple times over several days
After how many weeks should I be experiencing those aha! moments??
if you go looking for this as an end goal, I think you'll miss it and end up waiting a long time. It's much better to PR consistently over a longer period of time.
I speak both italian and english... if I learn how to photoread in english will I automatically also be able to Photoread in Italian?
Makes no difference