if you read this article,
http://www.overclockers.com/articles481/
he tested and found radiators to do better at low flowrates, adn blocks to do beter at high flow rates. this would mean we have to find a point were the two ballance out, or i had another idea.
it would use seperate pumps for the rad, and wb. the rad pump would be low flow, the wb pump would be high flow. the water woiuld be mixed in a liquid exchanger, could just be a resovoir.
i know that 2 pumps adds more heat, but the lowgflow pump wouldnt add much heat, seign as its low flow.