The exact number of pages that can be successfully hinged-in will vary from book to book. Remember, when pages are hinged-in, additional thickness (the Japanese repair tissue and paste) are being added.
Do not attempt to replace more pages than the width of the book spine will allow.
There are several options to use when hinging in multiple pages. One choice is to hinge the loose pages to one another as a unit and then hinge the unit into the text block. In another case it may be best to hinge each page into the text block one page at a time, especially if only 1 or 2 pages are being hinged-in.
The method needed will be determined by how you use the individual book.