I have to Green House White Rhinos growing outdoors right now. they are about 2 months old. theyve had alot of stress and growth stunts due to heat, transplanting and bugs but are doing great now. one is about 2 ft tall and the other is 1 foot. how tall do they need to bee for me to get about a pound betweem the 2 of them. i was going to let them each grow about 6-8 ft but privacy around me has been getting scarce. anyone know?