Spence is not an ordinary boxer, they have almost the same ranking, so he will not take it easy and will make sure he has some strategy that Spence could not counter.
On the other hand, expect Crawford to have some prepared strategies to counter Spence too.
Again, as I mentioned, it's about the good timing to execute their respective strategies. If successfully executed, that's a big advantage already as it will take a heavy toll on their opponent. And if one of them will continue to land a perfect blow, that will result in a possible KO win at either of them.
But for me, since they are currently the no. 1 and 2 at the Welterweight division right now, I'm expecting that they won't just play defense all throughout and care for the points per round. I want to see them challenging each other in close combat while saying
"I'm the strongest!".