I have to stick with EPUB because it is the customer's specification.
By "Adobe's implementation" do you mean the pagemap.xml? I read a reply from kovidgoyal that style=pagebreak:always helps speeding the "TOC" display and wondered if periodically entering it in a few of the <p> tags after every few pages would speed the display. Would replacing the pagemap.xml with additional info in the ncx speed it up?
Cheers for any help or comments.