How many orchids per square foot in a greenhouse

[Uechi]

I am in the process of planning a free standing hobbyist greenhouse for orchids. Is there a rule of thumb or fornmula for how many orchids you can reasonably fit in a greenhouse based on its square feet? I have a small back yard so the green house will have to be between 150 and 170 square feet. I realize that the size of the benches and the size of the plants will influence the number of plans allowable, but experienced forum members must have an idea. One can probably never have enough room however as I said I am limited by space. I plan on using the greenhouse all year. It is most important in the winter. I live in central Florida and I am am getting real tired of bringing in a 120 plants continually because of one cold front after another. I also don't want to be limited to those 120 plants. Thanks in advance.