I am planning on building a green house that is around 300 sq ft; should you order one from a kit or find someone who builds greenhouses? Do many people build greenhouses as a business (where do I find them?)? Are they more or less expensive to build? I live in Oregon, and we do get a little snow (not much usually, but every 5 to 10 years we do get a big snow fall that is around 3 to 4 feet). I want this to be a hot green house (not get below 65/75f at night). With all that in mind, do I want glass or polycarb glazing? How thick? Double or single? etc. I need to know as much as I can before approaching builders or ordering something off the internet. Thanks for any suggestions, recommendations, and answers you can provide!