Washing is always a highly emotive subject!

Ilford reckoned 6 complete changes should be ok for Archival puposes, and I've always gone for 8 as a slight sop to still not quite believing that you can wash so fast. Film is obviously easier, and you can get away with 6-8 complete changes over 30second agitation periods, meaning that your film wash time is about 3-4 minutes!

Major riders: Temperature. Very cold water is never gonna shift anything anyway.

Big temp changes lead to reticulation, and may even loosen emulsions if truly excessive. There is little if any advantage to going beyond 21c.

Don't overwork your fixer. Older fixer can be almost impossible to remove due to silver complexes. Check the capacity and stick to it. Two bath fixing can boost economy significantly.

Hypo-clearing paper may be an even better idea if you want to go this route in FB.

ALWAYS ALWAYS ALWAYS carry out a silver test BEFOREHAND to check your methodology if you intend to work commercially, or sell prints. Selenium toning can show up fix problems also, silver estimation products are the most expensive option.

Michael Maunder has pointed out that seawater is quite a good substitute for HCA in the wash process, and has some historical context...