The UC Davis refeeding protocol is a nice article and I think it lends itself well as a jumpoff guide, but one thing that worries me a bit is that the article seems to have become a popular "one size fits all" one page protocol. Someone with good intentions but not knowing could, for instance, misinterpret their description of how much alfalfa to feed by weight and frequency after a two-week period, stating it's then safe after 10-14 days to offer free choice hay; they don't say alfalfa but it is implied, and that could be harmful if someone following what is written in that article then lays out the alfalfa buffet and winds up with a foundered horse :(
Something I've done - again, depending on the individual horse - is to provide small amounts of grass hay too, the gut is waking up and remembering and wants to get busy, and I've found that small amounts of each provide more activity for the gut, and the horse is happier to have a little grass hay to nibble between alfalfa feedings which of course picks up those spirits.
Your stallion looks just great, bless your heart :) Did his noogies drop?