Paul,
I can't give you sf/person, but here are some data from Architectural Graphics Standards, 10th ed. for church pews:
With kneelers:
Front pew 3' 4" from altar rail, successive pews 3' 0" between the tops of the seat backs.
Without kneelers:
Front pew 3' 2" from altar rail, successive pews 2' 10" between the tops of the seat backs.
Pew length, as governed by NFPA Life Safety Code (1985) is as follows:
Minimum space per person is 1' 6" (Note: the table included with this information shows 1' 8" as the minimum size, and has another column for 1' 10" spacing.) Maximum number of seats on a row with aisles on both ends is 14. Maximum row length allowed is 21' 10", again with both ends open to an aisle. Arch. Graphic Stds., p. 635)
Classrooms:
Row spacing: 48" front to back, and seats spaced 27" apart, on centers. No mention is given of code specifications; these are general classroom guidelines for school classrooms.
I think you'd do well to grab a copy of that NFPA 101 Life Safety Code and use it as a guide.
Hope this helps.