Thank you for your advice as well.

I use Agfa Multicontrast Classic, Ilford Warm-tone Fiber and Forte VC Fiber papers.

I have been using just the one Non-hardening Rapid Fixer.... I suppose there's a more preferable alternative. When people speak of double fixing, are there two trays of the same or different solutions of fix?

I appreciate the technical description. I find it fascinating, and I need to embark on some serious research. The knowledge of how will no longer satiate my curious-want to know why.

I'm off to the Ilford site to read more.