Maybe a silly idea... but... what about removing the thermostat, unless you know you will be driving in freezing temperature ?
I'm sure the flow of the coolant will be improved.
Others have disagreed with me on this, but stuff on automotive engineering I have read has mentioned this.
While the flow would definitely be at maximum without a T-stat, that doesn't mean maximum engine cooling will be obtained. The coolant must remain in contact with the internal engine surfaces long enough for heat to be transferred to it, as well as in the radiator passages long enough for that heat to be removed from it.
Think about the T-stat's location in the cooling system. The only thing it has contact with is the coolant attempting to leave the engine. By making sure the coolant is hot before it's allowed to leave, it has assured that it has absorbed heat. If allowed to flow freely, the engine itself could theoretically over-heat as well as over-cool.
Added: In other words, the coolant could be circulating through the system as fast as the pump can push it, while the engine's internal parts slowly get hotter. This may not really make itself known until the engine is turned off and the extra-hot engine is now transferring heat to the stationary coolant, turning it to steam.
Depending on ambient temperature, engine and cooling system characteristics, operating conditions, etc., a T-stat could very well be gradually opening and closing during operation, thereby modulating the coolant flow in an attempt to maintain engine temperature within a given design range, or what we call "normal" operation.