I would lie to have two or three flip-books being played together at the same time

either one follows on from the second or both being played together in a joint story being told or the story using both and having a item flip from one to another for example a ball being thrown from one book to another.

I have also looked at sizing for my flip books 

 

This size is slightly to big there is a lot of room for the drawing however it is difficult to flip.

This size is easier to flip however this size doesn't allow much space for drawing at all a size in between these sizes would be the best size for me to use.