I'd take Ward. Ward didn't do muh moving, but he could when needed to. Almost all of Tarver's losses are to fighters who kept turning him and sticking a jab in his face. I have no doubt Ward would do the same.
I look at what Hopkins did to him (yeah I know Tarver was aged and weight drained, but Hopkins was even older and won 120-107), and I think in my mind Ward could do something similar