God help us if we have to rely on either one, but if we do, I'd go with Scal, (is this ME saying this?) ... after Sheldon's collapse at the Staples Center, I'd rather hang my hat on a guy that's been there before, and at the very least, has experience playing in "big" games, and a thorough knowledge of all the plays, rotations, assignments, etc..
He's not a bad PF when he keeps it simple, and he's also got the tres', which will keep the defense a little looser. Defending Sheldon is easy, and they're not going to worry about him on the perimeter at all ... Scal's still a threat outside, and that in itself is a big plus. Here's hoping we don't have to find out.