For the first time since installing the grill block I had the car on the highway for a reasonable amount of time. I noticed the full grill block certainly did its job. The ambient temperature was around 45F out. It took a little while, but the coolant temp just kept going up and up until around about 204F / 95.5C the radiator fan kicked on and the coolant temp quickly dropped down to around 190F. After that I turned the heat on and that kept the coolant temps in check. At lower speeds (45mph and less) I would be willing to bet the cooling fan would probably never come on.
Looks like that
actuated grill block will be coming in handy every once in a while even in winter.