Thanks! and thanks for getting that alternator bracket over so quickly ( I think I bought that from you ), that's tomorrow projectC (a name would be nice!);
Welcome to this forum!
When fastening torque is not specified for a bolt in a specific location, we can default back to a "typical torque range" for a given fastener size...and a mechanic develops that as a function of experience from similar sized fasteners where torque is specified (and maybe a few that he has broken off "not knowing his own strength")...
...or you can refer to the other rule: "Keep tightening it until it suddenly gets loose, then back off a quarter turn..."