I don't remember having any tool problems, but from your description it sounds as if you need a 10MM box end that is thin around the outside. I have one that is very thin around the outside and that might be why I don't remember encountering any problems with a 10MM hex size bolt.

If this is the case and I were you, I would buy a cheap 10MM box end wrench and grind it around the outside on the bench grinder until it is thin enough to fit.

Good luck,