I would give them two boxes if it were my big swarm. I would definitely feed them until they get established. I would put a queen excluder on top of the bottom board and no other entrances so the queen is basically trapped inside until she is laying. Consider lightly spraying the cluster before transfer with light syrup to put something else in their heads but getting the H out of the confinement. WIth the screen and kept in a cool place they will be fine til tomorrow afternoon. I would mist them with some water thru the screen. Just an ounce or two