I was not planning on omitting the openings, just glass or plastic. Hardware cloth only.If you get 90's in the summer, DO NOT......I repeat....DO NOT omit the side windows. You need them for summer ventilation. The way I did it is not hard, is cheap and effective.
And plastic over the scratch shed is good, but not clear. I'd stick with an opaque to let in the light, but not the heat.
You could use clear plastic roof panels for the monitor windows. Those can be fixed and need not open. My temps are still up after 5 years.
BTW, 5 years and still zero, zip, nada in the way of predator or any other death loss inside the house. A climate friendly Fort Knox.