With 12 11x15" (= 3 full) sheets (my usual batch size) of FAEW/SP, I use 4 water changes and shuffle all by agitating in the water + I lift each sheet out of water (from one corner) until drop frequency slows down to about 2 drops in 1 second (this is a very effective way of washing / clearing / agitating paper - highly recommended!), haven't measured it exactly but it takes something like 20 minutes. Papers work flawlessly with pop Pd and Argyrotype processes.