I do those sorts of centuries quite frequently every summer. Over the past several years I went from 700cx23->650bx42->700cx38 and now I've mostly settled on 650bx47 with a 42 in the rear, all slick tires.
They don't feel much slower on the road, although they are slightly, but they are a ton more comfortable and much faster on non-paved surfaces or aggressive chipseal. So if I were you I'd use the Challenge tires, but I haven't ridden tires narrower than 38s in a long time now so YMMV!