I think 37 would serve you well. Swing by sometime and check it out.
How much space is there in 37. Not sure on the availability of the passes, but if they are available, "space" is not an issue.
how much green area (we have a nice tree barrier) to look at. Not much green area, but the back does have some trees if that's important.
If we get there when the lots open each week, will we be able to find a regular location with 4 spots together? No problem. Some people get there early to get their spots, but as long as you pick a different favorite spot it should be no problem and you would still have a ton to choose from.
Will we have an issue if we host the normal 30-50 people? No.