If I remember correctly it was Ansel Adams and Barbara Morgan that in the early sixties defined and advocated archival processing of B/W prints. The idea was to fix well but not over fix to, treat against hypo with hypo clearing agent. To take care that each print would get thorough washing, to tone with selenium to increase permanence and to air dry to avoid contamination from dyer aprons. The Ilford Sequence is based upon their Ilford Hypam speed fix full strength. One minute in a used fix and an other minute in a fresh one but with a lot of agitation. During those two short minutes only a minimal amount of hypo can penetrate into the paper fibers and so you can wash in a shorter time. The fresh hypo bath and the agitation guarantees that the silver is fully fixed which is important for the washing because complex silver compounds that are formed by inadequate fixing are difficult to get out of the paper. To save time you can mix hypo clearing/perma wash(freshly made) with selenium toner (4 liters working solution with 200cc Selenium toner and 50 grams Kodak balances alkali). To my best of knowledge and experience this goes for all bromide and chloride papers