Why are you so concerned with excluding bugs with screens? No greenhouse is airtight enough to keep them out. If it were me, I would not lose any sleep over this. I have ordinary automatic openers in my greenhouse and I have never had any concerns about this issue. I'm not trying to belittle your post. I'm just suggesting that it really is not much of an issue in my experience.

Something else to seriously consider is that zero insects equals zero pollination !!! So having screens in place will also mean having to do a whole lot of pollination 'by hand' ... or limiting yourself to the very small number of available 'parthenogenic' hybrids that will set fruit without pollination.