Hello treed1304, I wanted to let your post sit for a few days, in case others might pop up here with a solution to the vent window problem.

I had the same problem with the vent windows on my HFGH. Even in the most "closed" position, the windows could be lifted open just a bit. I was not able to find a good solution, and the orientation of my GH is so that the prevailing winds loved to pick up the vents that small fraction of an inch, then let them bang down again. Bang bang bang. Too often.

I was worried that this would lead to a problem at 3AM when I was not there. Failing a brilliant fix, I finally gave up and wired the latches shut with baling wire. A few years ago, when we replaced our roof panels, I removed the vent windows entirely. I was only able to do this because I replace my south wall with screens all summer, and I use an exhaust fan to pull air through the open doors during daylight hours (through a curtain made of Aluminet.) Otherwise, I would not have been able to give up the venting.

I think this annoying problem is present with most of the HFGH kits. Maybe, it's worse for some of us, depending on wind direction. So far, nobody had posted to my blog or here with a good fix.

It's possible that equipping the windows with hydraulic automatic openers will resolve this problem. I never tried this, but I've read here that the automatic openers sold by Harbor Freight don't work well (or, for most, don't last long.)

I'd try some of the other brand auto openers instead...by Bayliss, for example...after doing more research.

Maybe...some brilliant person will show up here with a better solution (hope springs eternal...)

Looking forward to seeing pics of your project!

Thank you Mudhouse. I will be going the vent fan route next spring. I will just wire the vent windows closed for now. Primary use I intend is for plant starts for our half acre garden in the spring so venting will not be an immediate issue.