pbdechant:
I believe that the balance arm is parallel with the bottom of the balance wheel and if so, then I think the balance staff will need to be replaced with that orientation in mind. It should be pretty obvious, but what I always do is go back to Bob’s videos just as a refresher. By doing this, I have saved myself tons of grief. I think it’s staffing videos #5 and #6 – the last two I believe. You have asked some very good questions – especially BEFORE you do the work. 
Don’t forget to take plenty of pictures for each step in disassembly. You will not regret it!
I hope this helps,
Tom