4mm twinwall polycarbonate insulates better than glass, and my MIL has been growing tomatoes in a glass GH, so these greenhouses should be fine for the purpose.
I spent last night reading the other forum (and was really annoyed by the adds covering my screen, before seeing messages). There is a lot of info about these greenhouses and how to modify them. My DH is better than average handyman (top reason to keep him around
), so he could strengthen the frame.
Dollar is so low at the moment that it makes buying these greenhouses really tempting. At the moment we should buy everything we will need in near future here in U.S. and move the stuff with us, because it does not make sense to exchange our USDs to Euros. Similar greenhouses in Finland are now at least 4-5 times pricier than these. We have saying that "poor people should not buy cheap stuff", but this may be too good deal to pass.