If you don't want to spend the money on aluminum pulleys ( I wouldn't if you don't have to) just use a spacer behind the WP pulley. I do it all the time to get all the belts to line up.
For the smaller waterpump pulleys out there I've seen, I'd have to use a spacer behind the crank pulley, since the smaller water pump pulleys are shorter the the one I've got. This is likely the route I'll go if I can't find a longer crank pulley.
