There have been little bits and pieces of metadata information posted on this forum, but no comprehensive guide has been written due to the fact that most people playing with it don't document the effects of changing a certain bit to something else, and the ones that do only document a small portion of what they really tested.
It's a very tidious task that would take a long time to test each weapon/object/projectile/etc. Unfortunately, not many people have a whole lot of interest/know-how to hex edit and reload a map over and over. An ideal thing to be devopled is an on the fly hexeditor (ie: a code search in an emulator), where you can see the changes as you apply them. I don't think it's possible to write something like this, maybe with debug xbox.
Anyway, I hope you're able to accomplish whatever you invision for this project. Don't let the hurdles discourage you. I don't know how much interest dmauro, boll, or the few experienced people have in teaching people "down to the bit" meanings in the metadata information. However, it never hurts to ask for assistance, unless you expect it from someone. Keep up the good work.