The only proof you can generate that photoreading works will be when you use it. It requires no practice, as it is a natural ability. The only reason you should do it often is to get used to those feelings you attain when the subconscious feeds information to the conscious mind, mostly it's through suttle images or feelings.
Don't count the hours, the books, the pages, or speed.
Just use the system to get the information you're looking for. And just do it, don't worry about "does this work?", "what if I'm not getting anything from this?" because it doesn't work, you do, and you are getting information from the book.
You don't practice the dictionary game and as a matter of fact do it just one time. That's what I did, that was my proof. It was way to on point to be a coincidence.
Play with the dictionary game, because it's a GAME, not an exercise which must be done to get better at this.
The only way to get better is to do it more often, as then it will be more natural and small mistakes you might think you're making will begin to disappear and you won't care anymore.
Also, don't be obsessive, it's much better to have a passive attitude. Being obsessive will create expectations, and if you don't live up to them, will just disappoint you.
Set goals for yourself, and build on them. First goal, "photoread 20 books this week and activate at least 3."
That's the type of goal to set for yourself at first, as you'll be using the system and becoming more acquainted with it.