For topping up O2 bottles, have you looked up in Chapter 12 of the MM? I am only guessing, but that is a good place to start. Failing that, Chapter 38 (Oxygen Systems)
For brackets etc. do you have access to the aircraft manufactures drawings? Everything you ever needed to know, including heat treatment requirements is there on the drawing. If you don't have access, then ground the aircraft! It is surprising what happens if it looks like hangar space is being taken up by an aircraft that is stuck for a little bit, but you cannot get it because of management shortcomings.