RE polishing metal, especially brass
Remove it from the wood first. Metal polish kills the wood. Especially Brasso, and liquid polishes, which seep into the screw holes and causes rot.
Be content to use Pledge or simple spray on polish for the bellows, especially thin leather. It is easy to make the cardboard stiffeners unglue themselves. Never use neatsfoot oil, or armorall.
If your screw drivers don't fit perfectly, buy a new one and file it to fit.
Do less than you think you should. Consider the era of the camera. Find reference materials from that time for finishes, and metal work.
Be careful when working from guides by 'repair authorities'. There have always been many technicians, some of them good. Not many good ones ever wrote how-to books.
Have fun !
"This suspense is terrible. I hope it lasts."