Well, we don't get thunderstorms here.

I have two vents (HF....many people deride them), one low on a west wall and one on the east roof pitch. They open just about every day unless it is utterly nasty outside (like you would not want to go outside and garden). They sort of follow the sun, so the upper east one opens early as the sun heats up that side of the greenhouse and eventually the lower west one opens and flow-through commences (I live at the coast so prevailing winds are typically west to east). They close as the day begins to cool and the sun sets.

I'd hate to think what the temperatures would be without the vents because they hover in the high 90's to low 100's when the sun shines and the vents are wide open.

I have a self-built 6' x 6', so it's smaller than yours. My mistake was in not making the windows large enough. Ironic, because when I was starting to assemble I thought, "I made this window way too big, better fix that now".

Duh. I'll fix it when the plastic needs replacing somewhere down the line.