The expected negative effect of being KOed is
(expected action points lost due to being KOed) = (probability of being KOed) x (action points lost when KOed)
Stonewall affects the negative effect of being KOed through the probability of being KOed by some modifier, so
(modifier) x (expected action points lost due to being KOed) = (modifier) x (probability of being KOed) x (action points lost when KOed)
Make quick recovery affect (action points lost when KOed) by the same modifier, so that
(modifier) x (expected action points lost due to being KOed) = (probability of being KOed) x (modifier) x (action points lost when KOed)
This way the benefit of picking either perk = (1 - modifier) x (expected action points lost due to being KOed) = reduction in the expected time lost due to being KOed is the same for both perks, but people have a choice between getting KOed less or being unconscious for less time.