Well, I didn't get the roof lifted within the time frame I needed it done. I was concerned about the framing supporting the added weight, so I waited.
I want to say thank you to everyone who responded to my post...
This is what I ended up with:
● The misting system I installed was a little too wet for the run coming from above. I switched it out for a misting hose. The mist shoots Straight up and onto both coops, but it settles just short of getting the run wet.
● I installed a light carrwas shade tarp beyond the misting hose about 18" off the ground. It forces the wind coming across the run to come in lower and across the cooler ground rather than the blowtorch-like gusts which are the norm. It likely does little to cool the coops, but the run is much more pleasant.
● I made zero changes to the coop in question after my original post, but here's a picture I took yesterday showing my temporary solution for the nesting boxes. The opening is covered in hardware cloth.
It really does nothing to improve ventilation, but produces a minimal draft that helps a little.
● Finally, I moved my lone hen from the original coop to the new one. The original coop vents better, but she's more "hardened off" than the chicks who I placed in her coop and run. She was NOT HAPPY about the change, and she ran in circles for about an hour before laying in the new spot. She did the same at bedtime, but as soon as it got dark she roosted up in the new hen house.
This will have to do until my darling husband comes home in September to raise the roof and install windows. It is likely that I'll have the flock integrated by then and they'll be roosting together in the original coop before that time.
thanks again for all of the input.