The full block w/ only the bottom slot on the top grille open ran too hot for me liking.
It was a cool day and the scangauage got to 225 water temp on a highway drive to New Bransfel, about 40 miles away.
I pulled off the entire upper grille and ran w/ that for 10 miles. The highest temp was 195.
Next I cut off the top slot and put the grille back on.
High was 215.
I'm going to see what my comutes look like this coming week.