[Callers] dance floor capacity

A space conundrum for you all. I'm calling a wedding reception for approx 150-170 guests with a designated dance dance space of 35 feet x 16 feet. No options for expanding or last minute venue switches. (Also note that the band rather than myself was consulted on venue space. I've seen the diagram, and the space is at least well-used. The dance space is arranged lengthwise at the end of the large hall next to the tables. ) How many people (non dancers) would you realistically expect to get onto this floor at once? I'm contemplating some circle dances, some scatter mixers and some longways sets. Maybe a single file spiral around the perimeter of the room. The guests are mostly non-dancers, occasional contra dancers and a few Scottish/ceili dancers thrown in for spice. I don't think I can get all 150+ people into that space at once. Thoughts? Calculations? Joy Greenwolfe Durham, NC