I Think with a cattle panel frame you will need bracing to keep it from swaying in the wind.

personally the only cover I use is 6mm greenhouse film with uv protection. it should last 4-5 yrs. minimum.

I don't know about using it with cattle panels as there would be so many rub points.

For a low cost greenhouse frame the portable carports are excellent. just frame the ends in. Very sturdy and you can expand if needed.

cooling is just as important as heating, you will need a way to exhaust the heat as they get hot quick in the Oklahoma sun.

I am in south-central OK and have a hoophouse type greenhouse with a frame made of wood and PVC pipe. To keep abrasion from tearing the plastic when the wind blows, we have batten tape between the PVC pipe frame and the greenhouse plastic. Different kinds of batten tape (some are vinyl, others are felt) are available from greenhouse supply stores and probably on Amazon as well. And, the use of the term "when the wind blows" doesn't mean your plastic will rip every time the wind blows, but just that the constant abrasion from the plastic rubbing against your greenhouse support material, regardless of what it is, will eventually cause holes to develop. I've found my greenhouse easily endures routine gusts in the 50s and 60s. I don't believe it ever has had wind any higher than the 60s, but expect it ought to tolerate wind gusts even into the 80s. I cannot remember the brand name of the greenhouse film, but it might be Poly Tex. I know it has the word Tex in it.

Like Robert, I use only real UV-stabilized greenhouse plastic. I like it because it stays clear (as opposed to the so-called clear sheet plastic you could buy on rolls at a big box hardware store, which quickly turns cloudy). My plastic is 6 mm too, and it has been on my greenhouse for 5 or 6 years. It still is in great shape, likely because we have the entire greenhouse, except for the east and west end walls which are filled with doors and vents, covered in 50% Aluminet shade cloth. Even with shade cloth, my greenhouse hit 100 degrees yesterday, when the outside air temperature was 89. Had I not had doors and vents open, based on prior experience, the temperature in the greenhouse would have been in the 130-145 degree range. I usually have everything out of my greenhouse before May arrives because it just gets too hot in there, even with the fan running and all doors and vents open.

My greenhouse mostly gets used from October or November through sometime in April. I use it to overwinter a few tender plants in containers, and to grow lettuce (and sometimes a few other things) in the winter time. I also raise tons of veggies, herbs and flowers from seed. They are started indoors in a heated room at the proper temperature for seed-starting, and on a light shelf. Once the plants are large enough to tolerate the fairly cold nights in the unheated greenhouse, I move the flats out to the greenhouse. Because of the shade cloth, I carry them outside in the proper manner to harden them off over time. The main reason we built the greenhouse was to give my flats of seedlings a safer, wind-protected spot in which they could grow on for a while until the Spring weather stabilized enough for me to put them in the ground.

In our climate, it is hard to use the greenhouse in the hot months unless you run some sort of cooling system and have fans for air circulation and vents that you can leave open pretty much 24/7 once the heat sets in.

Thank you both for the pictures and information. That gives us a lot more to think about, and visuals to go off of.

Mine is cattle panel frame. Here is how I built mine.I put 2 of them side by side and welded them. So now they are 16' by approximately 8'. Then I bent them over in an arch, longways, held the arch with a ratchet strap, and built a wooden frame to screw the ends (now each bottom side of the arch) into. The frame is a rectangle with the floor dimensions I wanted. I set the arch ends on the inside of the rectangle, and sandwiched the ends with another board and plenty of screws. It is solid. So now the wooden frame holds the arch shape. I took off the ratchet strap and commenced to frame up a door on each end, using some metal I welded and some wood I bolted to the metal. Then I built the doors and covered it in plastic. It does not sway in the wind and I stretched the plastic tight enough it does not rub through. The dimensions are about 6 1/2 - 7 feet tall, about 6' wide, and about 8 feet long. If I think about it I will take pictures this weekend and post them. It is tight but I have built two shelves, and also I can hang pots anywhere I want inside it. If you wonder why I chose this method, all materials were free.