TBH, I'm not either. Looking back at the difficulty Spence had with Brook, I think Norris would be wrong for him.
I think Brook was tougher than Norris physically, but otherwise, leagues below him. If Spence can impose himself and break Norris down by going to the body, he can win. If he can't - which I'm inclined to believe more - then he likely goes from being frustrated by Brook's athleticism, to losing most rounds because of Norris'.
