Proof temperatures

I'm curious to know what temperature is ideal for proofing in the B & T proof box.  Some of my bread baking cookbooks specify a particular proofing temperature or range of temperatures, others mention proofing at room temperature, and others simply say to proof until doubled.  I don't own the proof box yet but what are the recommended temperature settings?   Or are we simply looking to create a constant temperature and can gauge by a doubling of the dough and not by time or temperature.