Just change those screws to Dzus fasteners and you'll be good to go. Modify it by cutting it in half for further adaptability.
FWIW, even on a 75 degree day here while hauling a half ton of dirt, our truck provided no hint of an overheat with the grille block in. (But the radiatory is arguably oversized for heavy loads anyway.) I'd wager that most vehicles could stand to have the block in more often than not.
In terms of automation, I say run a solenoid, like the ones that pop doors, with the radiator fan switch on your spring loaded shutters. Normally, the force of the spring keeps 'em closed, and when the fan turns on, the door solenoid/s pulls the metal cable/s attached to them to open 'em up. Or just use a metal cable run into the cab, that's what I was planning on doing. KISS.
For Saturns, a radiator fan switch solves all your problems. The counter-intuitive trick to lower coolant temps in a Saturn is to turn ON the AC because that always makes the electric radiator fan come on. That mod is on my short list.
Thanks everyone. So far, I haven't had problems with overheating, so no need (yet) to punch holes or louvres or whatever. Modding it so it has a sliding panel is food for thought. And, yeah, I suppose I should have done something temporary that can be quickly modified with a knife while on the road. I haven't gone thru a tank of gas yet, either. Unfortunately, whatever savings the grill block gets me on this tank is going to be overwhelmed by the recent change in the driving I have to do. Been spending a lot more time in rush hour traffic, with thrilling consequences like having to wait through 2 or even 3 cycles of some stop lights.