I forgot to talk about this at La Selva, so here is my personal take on removing pages. I remove pages when I see that the book is getting thicker than I want it. If you glue several pages together, or glue on heavy embellishments, you will need to remove enough pages to allow the book to close - if you want a book that closes. You don't need to do this if you don't care how flat the book will be. But, think of how you want to store it and display it. That will help you decide what is right for you.
When you remove pages, dont' take them out in hunks. I take out one page here, another there, tearing or cutting at least 1/4 inch from the stitching in the binding. You don't want to destroy the integrity of the binding or the whole thing can fall apart. I do this on an "as needed" basis.