48 mins to get full train, and i never had players with to bad form when they played 48+, so that should be enough i guess
24 that you dont loos stamina, if i got a player above 24+ the form is kinda medium i think.
but 80 mins your player probably raises to good form if he had very bad form before.
but not 100% sure, thats just what i think, maybe we get more answers in here.