Limit on number of scrolls per "Holy Canon"? Seems to me that you can't really have a book over 300 pages without having trouble binding it. I will have 'Bookbinding' as my skill. And it would probably take me a full minute to switch between one book and another.
I'm fine with giving up Turn Undead for Scribe Scroll. I'll be lacking out on a class ability that opens a lot of doors for me, but I'm confident I can do without it.