what your talking about helicopters wont notice, if they even are looking.

the only way your gonna fit properly matured plants in that case is with lowryders, which arnt the greatest available strains.

id suggest finding a small closet space of 2X2X4 and installing 5 or 6 23w (100eqiv) CFL bulbs and grow 3-4 good plants at a time. If you do this, make sure the lights can be raised or lowered and look around the site for more info