Bob308, I hear ya about keeping things as simple as possible, do you find constantly circulating coolant through the heater core (no shutoff valve) pumps heat into the car when you don't want it to?
Mike G, the mention of restrictors brings up another question, how much circulation is enough for manifold heat? Usually you see a 5/8" heater hose diverted to heat the manifold. Is that overkill? Would a 3/8" or 1/2" line supply enough heat?