You could try a medium. Just take it off early enough to feed them so they have time to fill the top deep with stores. They may ignore the medium and fill the top box anyway.I know we don't have 8 frames of drawn comb to put in it, but would it be worth putting it on, for them to "get started on?" Or would be be just giving them a bunch of empty space that will be dead cold air?
Would a medium be any better? Again, I don't know how much drawn comb we'd have to put in it.