Hmm, never really thought about tolerances. Ages ago when I was responsible for a b/w process line, the steel reels were lobbed back into a storage bin after use - hate to think how bent they migh have been! Still, they tended to work ok or we might have just filtered out the difficult reels as we went along.
I think that the suggestion that when the film won't load then the accepatable tolerance has been reached is a good one !
Hope you get them to work.