Huge Country should take this. Most of Derrick's wins are KOs, and Roy has an amazing chin. Most of Derrick's KOs are gnp KOs, and he's not going to mount Roy.
Roy should have an advantage on the feet. He is known for his big right hand, but he throws more than overhand punches. He can be tricky. Lewis is an imposing figure, but he's not a fast one.
Roy's bjj will be there if he needs it. He may not get a sub, but he can find his way to the crucifix. And he will keep himself from being mounted.
Lewis has a lot of strengths: power, effective gnp, deceptively decent cardio. He can win this. But Roy is the easier pick.