Here are some thoughts.
Some papers are sized with Aluminum based agents which act as hardeners. Therefore, it may or may not be best to use a hardening fix with them. Some emulsions contain low bloom gelatin and harden differently than high bloom gelatin. Best conditions differ for these situations.
So, as pointed out, the final use of the coating as well as the support will determine the best conditions for making up the emulsion prior to coating and during processing.
Sorry I cannot give a straighter answer than this.