You might makes some test baffles with cardboard of different shapes and configurations and do some measurements to test everything out. I'd experiment with smaller baffle sizes to shift the frequency up so measurements would be easier. Maybe try 9 inches to a foot, using a small midrange driver. The higher in frequency you go, the smaller the distances involved and the easier it is to gate out reflections from walls and stuff. Once you have defined properties, you could scale up to the size you want and go with a larger driver for your 100Hz model.