Running without a thermostat ok?

The trick here is to get the cooling system to opperate well enough that it tries to close the thermostat. I doubt the length of time coolant stays in the radiator will matter much, as the longer it cools in the radiator, the hotter it gets in the engine. Heat transfer and fluid flow equations I'm sure will bear this out. After the engine reaches 200 degrees every typical thermostat will be open all the way and stay there, no matter its rating, and if it is functioning correctly. You now need the system to keep up. Make sure the radiator is clean and not blocked, hoses are not collapsing, block is clean, fan is correct and belt tension is proper. Shrouds seem to help, but I have had good luck without them, however I do eliminate the clutch fans. They will slip a little under hard acceleration so as to allow a little more power to the drive train, but I always figured that's when I needed the most cooling.