It is possible to maintain separate reagent files, by backing up the reagents.gst file in your save folder and then let the game recreate an empty one when the game is restarted. However I believe cloud saving must be disabled first, because I would swear at some point the game magically put them back after I had deleted them. I also experienced some black screen issues for which it is unclear to me right now if they were caused by me toying with this file to create an SSF character
EDIT: just found out my issue is likely this one, so not related to swapping the reagents file: