That is a very nice safe that deserves the effort to get it operational again. Unfortunately, there are not many who have a good understanding of the mechanics of this safe or other brands of cannonballs. There are even fewer who are willing to share their knowledge.
Doug has been an invaluable source of information for me (and many others) with my safe projects even going out of his way to provide a rare bolt missing out of one of my Mosler/Yale 5H locks. I would review his answers as your question was answered.
I too like to do all aspects of my projects, but at times I have to swallow my pride and seek assistance from those who know more than me. Each time I come away a bit smarter. Keep us posted on your progress. It is always fun to see these beauties preserved.