Where does something like Ilford "Washaid" fit in all this. Or is it more of a paper wash aid.
Washaid is a hypo eliminator, not really needed with rapid fixers and film, probably not needed with rapid fixers and RC papers either, since the chemicals don't get the opportunity to get absorbed into the paper in the short fixing time. Fibre base paper, yeah, especially if using a traditional hypo fixer. If you have a huge jug of the stuff, then feel free to use it, if your thinking of adding it to your next shopping trip, then unless your using FB papers, I would skip it, get the Ilfotol wetting agent or a jug of Photoflo instead.