Probalby the best source would be GE if they still have the Instruction Leaflets. When I was in the nuclear business, a division of EPRI called NMAC (Nuclear Maintenance Applications Center) published a Circuit Breaker Maintenance document on the Magne-Blast bkrs. It is a wealth of information on these bkrs. It is licensed material, I can't give it to you.
Is there anything in particular you need? I could probably send you the list of references used in the document.
wbd