Great to hear that you like Saltprints an extremely underated process, that is unmatched in subtleties of tones imho. I'd use
Sodium thiosulfate rapid fixer bleaches to much. If you keep your prints mostly in the dark you can indeed use the salt method. Both salt and Hypo will change the color. When using rapid fixer it is even more important to tone the print before fixing either with Gold or Platinum toner

Dominik