A set list , for your regular 45 min set x two , will be around 10 - 13 tracks per set, ( say 20-26 all in ) give or take depending on how long they are and how much babble there is between songs.
Ask the band to make up the list for set 1 , and get that rehearsed, then again for set 2. They obviously have a lot of spares for longer gigs, or if they like to juggle the set lists about.
It's a bit much to throw 40-50 songs at you straight off. They'll need to be patient.