Someone's panties need to be changed.
Partially blocking the radiator will help regulate the temperature in the cooling system, keeping it at operating temperature when it's cold as balls out. Sure, warm the car up to operating temps, then go drive it at 70mph in 0* weather and watch it go back down.
No, you should not block the whole radiator, and no it won't help it warm up any if the thermostat is functioning properly, it will only help maintain that temperature.
there is ZERO NONE NO NO NO coolant flow when the thermostat is closed.
I don't want to play on technicalities, but the thermostat is designed with a weeping hole, or some other bypass method.
Any ideas how much get past this? I know on my truck there is an entire by-pass system to alleviate strain on the coolant pump. It puts out about a pencil-sized stream of coolant straight into the expansion tank. I would like to know how much this system is designed to allow through it.