true well legal or not,its a bitch when the cops come.u can still be arrested and have your equipment seized "total pain in the ass to get back"
but trying to answer your yield question basically there are wayyyyy 2 many variables 2 throw out there,i could tell you if this is your first grow and every thing is perfect dont expect your yields to be spectacular.i would throw out an ounce per plant with no experience,do a couple more grows and you could pull 3-4 ounces a plant,like i sed wayyyyy to many variables.i think the best advice i could give to you is be plant specific,get a couple different strains and keep mothers,do several grows with the same strains that way u can learn more about that particular plant and how to maximize her potential.i have friends that have grown the same strains for years and by using different techniques,nutrients,grow set ups, they have been able to perfect yields of one strain.i hope that makes sense