When I was at Uni first time around, many years ago, a few of us made a greenhouse out of plastic bottles, strung on canes. built into a 2x2 wooden framework, with a slightly angled roof. Issues we faced were:
-Bottles come in many sizes and obviously they all need to be the same size, and transparent. It took ages to collect enough even from amongst all our friends.
- Angling the roof created some awkward spaces to fill, and although the gaps did let excess heat out in Summer, we ended up taping thick polythene sheeting over the triangular areas for the Winter.
- Rainwater came in through the roof as the bottles, even pressed together tight, let water through, and we tried to seal them using aquarium sealant, which turned out to break down in sunslight so again heavy plastic sheeting was used, but this cut down on the light a lot
Just some thoughts, which I hope help you work through your design
Oh, and the bottles did last several years, and we grew a lot of very tasty food to supplement our meagre student diet at the time!! I wish I had some photos of the structure but we never even had a camera between us