Thanks for your replies. They have explained a lot.
I've also had problems with my 505 rebooting when repaginating and didn't realize that was the problem.
Assigning so many pages/kb also makes sense, although for some inexplicable reason I still prefer to see a page number/screen.
I think I'll use LRFs for the books that don't crap out when repaginating and get over my pagination neurosis with those that do. I'll also try Toddos' suggestion.