every plant and every harvest yeilds different. but what did you guys come up with. dry weight? pics of your 3 plant scrog?
do a search and do the math dude, lots have done scrog on here,.. hell im doing one now! (link to it in my sig)
there's is not a specific answer possible for that question.. it all depends on the ammount of time you have and how many plants you use... if i had 5 months for veg, then i could have a one plant scrog that has a bigger yield than a 4 plant scrog with only a month of veg, if i wanted that same yield but only had about 4 months for the whole grow, including veg flower and the 2-4 weeks you can't even count between the 2 stages, that too would be possible but then you would need a hell of of a lot more than one plant. just as a guess....i'd say with 3-4 weeks veg time, your plants will probably just be hitting the screen so just slightly more than a normal grow with 3 plants. then i'd say possible, for every extra month of veg time you could come close to doubling your yield at final harvest, because in a months time the plant should be able to come close to doubling the ammount of flowering tops that will all be on a level surface, the screen (meaning they will all get equal ammount of light. the whole point of a scrog)
this video here: http://youtube.com/watch?v=bIq_SX5KlLM&mode=related&search= is a good example of what balla420 is talkin about. it is just one plant given enough time in veg (and in a big enough pot) to support many many buds using the scrog method. this one plant yielded 114 grams dried (lil' more than a QP). the guy shows so much yield but aaah it's ONE plant!! also enjoy the vid it has lovely buds!