[Christ]

It's going to be really hard to tell what the grille block will do for you until you actually test it out for a few tanks.

Here's how your thermostat/radiator works:

From dead cold, you start the engine. The tstat is closed, so coolant only circulates (via water pump) in the engine (and possibly heater core, depending on your setup). When your engine reaches (in your case) 195dF, the thermostat opens. This allows your (now hot) coolant to enter the radiator. For every action... Now, cold coolant enters the engine, via the other end of the radiator. When the colder coolant hits the tstat, it snaps shut, to allow that coolant to come up to temp inside the engine (195dF), then cycles open again, so on, so forth, until all the coolant reaches op-temp, and even then, the tstat still cycles open/closed periodically as the coolant cools down/heats up.

A grille block merely allows less direct airflow over the radiator, which affords less cooling capacity (not necessarily a bad thing) to the coolant, so that when it is able to re-enter the engine, it's warmer than it normally would be, takes less time to cycle back to 195dF, which means the engine warms up quicker than normal, with less heating/cooling cycles of the coolant before stabilizing.

The other thing it does, as a consequence of blocking airflow into the radiator, is push air up and around the car, as opposed to through the engine bay. This creates less of a parachute effect, at the expense of cooling capacity. Since cooling systems are designed on a worst-case scenario basis, you can afford to lose much of your cooling capacity without even breaking a sweat. Don't make anything permanent until you can verify that it's helping, though.

Also, check that your fan's thermoswitch is set to a temp higher than 195dF, else it will be coming on and defeating the warm up cycle anyway. It should come on at like 205dF.