Well I know that in Adobe Acrobat if your books don't have a secure feature on it that prevents you from doing certain editing you could combine them. So you could make one giant PDF and then set it to auto scroll the pages to the end.
I usually set Acrobat to view two pages at once and use the page down feature when photoreading eBooks.

Also, I flip the book upside down too and photoread it that way.
At the recent retreat I asked paul does it make a difference and we turned over our books upside down and we could still easily read the material. Also, he said no it doesn't make a difference in the order that you photoread it in too. Since once you got it in the information is inside you, which is the important thing.

It was a very interesting thing to see.

Mirko