How about running your line starting at the rear drain on driverside to the manifold, then out of manifold to the thermostat housing?
I am with tlowe . . . the rear drain-cock forward to the water pump seems the most direct route to take:
Inlinter's post circa '13 
The direction of flow is from the pump pushing coolant into the block. In stock configuration the only way for the coolant to get out is for the thermostat to open. By tapping into the draw side of the heater circuit one creates flow through the intake even when the thermostat is closed.
Using hard lines is clean up top - and the balance of the plumbing can be muted with paint.
regards,
stock49
