A new distraction from the oh-so-witty banter...

I am looking for information on the hardware choices between new galvanized
steel shelf angles that are to be bolted back to existing steel brackets.
The steel shelf angles at most floors of a 1920s high rise are consistently
deteriorated and justify replacement with galvanized steel angles.  These
will be bolted back to the existing and thankfully better protected steel
bracket system which transfers the load back to the steel structure.  My
question relates to the hardware.  What is your experience / theory  /
general philosophy on  cold mechanical A325 SC bolts, galvanized hardware,
or only galvanized nuts and washers, or using a nylon/ neoprene separator at
the washers?

Thanks

Mary Brush
Klein and Hoffman