If you are American, I think of the D&D system like the US Court in a sense. 

>Creators of D&D(Legislative Branch) make the rules. 
>GM's (Judicial) interpret it, making the game's differ from GM to GM. 

In this case, however, you are both. So I guess the only thing I can say is this: Make sure you have enough guidelines to at least have pretense for when a new situation pops up. 400pages+ isn't really needed, but just so we know what to expect. Something so we don't mess up and get our character dead because people didnt know the rules. That's all I got.