Ya know, I STILL can't see myself as "petite"

I've long feet with a narrow heel, and sizing has always been a bear for me. My shoe size ranges from an 8.5 to 10 depending on who makes the shoes and what type they are. This is just wild to me, but there isn't any standards.
I've been told that Sidi and Mavic are European style, which means a more narrow heel. I don't know about that, but I do know the Mavics fit me better than any other bike shoe I've owned or tried on. I am afraid to try on a pair of Sidis, trembling even (that is actually my checkbook trembling).