New HFS Group Starting in North Arizona

I represent a small group of players who split off of Amtgard last year. A couple of things I had wanted to ask:
1) Is there such a thing as a game-wide corpora, governing body of laws, or some other such rules to go by?
2) I noticed that some groups have kingdom specific rules, is there a limit to the rules adaptations without breaking away from the "brand name" so to speak.
3) I am having problem finding HFS non-kingdom specific rulebooks online. Where can I obtain one?