I'm thinking of a bakery with enough space up front for 4 small tables with 2 chairs each and an office closer to the back for consultations. What would be the maximum occupancy for locations of a certain size?

I would think you need to talk to your city/county health or ag dept.  Maximum occupancy would be determined by the size but I would think  certainly w/just 4 table & 8 chairs you wouldn't need much more than a space 10"x10" if even that.   To me more important is how big a work area you would need to hold all the required sinks, work tables, ovens, equipment/ingredient storage

Mine is 16 x 20 with an 8 x 7 pantry off the end. It is barely big enough, and that's with storing plateaus and extras in the basement. There is no room at all for a separate consultation area. I'd love to have that, but honestly it's kind of a waste of space. I use my 8' decorating table for consultations with them on one side and me on the other and it works fine. I have chairs for "bonus people"