14' x 12' (168sf) is a very good benchmark and recommendation yet today! Please keep in mind the foot print of each item in a booth.
Single projector (pedastel or console) (42sf), standard size platter (49sf), make-up table (20sf), sound equipment (16sf), minimal trailer, film can, lens, bulb and supply storage (9sf). Total 136sf minimal. These totals include minimal service space (i.e. room for service panels and doors to be fully opened and room for an operator, tech or engineer).
Any other items you wish to bring into this space will eat up the remaining 32sf recommended FAST!