If I grew in a tent I would want at least a 2 sq ft footprint per plant. Then you need to consider equipment that would also possibly be on the floor and room for you to move around for maintenance etc.
Take the sq.ft. of the tent (100 sq.ft. for a 10x10) and divide by the sq.ft. of floor space you intend the plant to cover. For example, if the plants cover 4 sq.ft. each, which would be 2 foot wide and long, you divide 100 by 4 and you get 25 plants.
Do you need a tent? I have an open floor with panda plastic panels I can move to expand and I use black out curtains to divide my rooms up. I use a 1000w hps I can get 6 - 5 gallon buckets around the edges and 4 smaller plants in 3 gallon underneath with my umbrella reflector. + I can move my vegging plants in during the day then back at night in the few spaces I have left where I can stand a plant. My veg room is a closet 3x2.5 x 6 ft...the flower room / space is about 10 x10 x 9' ...I collapse with the panels to about 7x7 with fans in the corners