I think it's in the 4-6000 sqft range but there are many projects during the year, so I can't say with certainty.
I am told he sees foundations that routinely are off several inches from true level.
Not sure.
I think I shouldn't have mentioned this specific application because it's kind of derailed the conversation. My larger interest was in coming up with a cheap/effective way to measure cut length on a chop saw while standing only at the saw itself.