You're making a mistake to allow previewing to take longer than 8 minutes. You're not reading at this point and if you only manage 18 trigger words that's your start.
Previewing is not reading, don't waster your time on it. I spend about 90 seconds on a preview 8 minutes is the most. You you find yourself spending more. Don't preview more than 90 seconds and do a 12 minute postview instead.
Getting into the accerated learning state only take 5 minutes even for beginners.
PhotoReading - if you have trouble with the blip page use soft focus. You don't need the blip page to PhotoRead and don't waste time trying to Photofocus every page... use the Imaginary X-Technique. Turn the page in rhythm and say the chant. You should be turning one page every two seconds. Sorry no if or butts here 
As a PhotoReading instructor I know the times I cite are more than enough. If you're giving it too much time in the beginning you can bet you're falling into every passive reading trap there is.
Check your purpose and work within the times cited for training yourself to get it done within the time there is. We have a common misconception that we have all the time in the world to read a book. This is not the case. There are other things to do that are more important. Tell your mind to stop being a wussie and set the timer. When it goes of you're done check what you've achieved. You'll probably surprise yourself.
Alex
[This message has been edited by Alex K. Viefhaus (edited March 09, 2005).]