You guys should go check out Veg's thread in the outdoor section. He does it big, real big. Veg can be a little callous, but mostly helpful and right imo. I read some scientific papers on ventilation too, with extraction and circulation both shown to be important. Laminar and turbulent airflow or something like that...
I'm tagged on his thread and many others. I try not to talk shit. I'm THRILLED he wants to chime in and help - if that's what he's doing. What I didn't like was the confrontational "you'll be sorry!" way he phrased it. (And I said as much.)
If anybody here is reading my posts as if I think I know everything, please take the time to read the small print in my signature line.
Thanks to everybody for their thoughts, ideas, suggestions, criticisms and most of all for your interest and support.