they will double to tripple in size, can you raise the light up to the top of the room? if you can wait untill they are 4 feet to flower, if not, just devide the maximum heigt by 3 (its an indica, will not strech as much, but 3 to be safe. you will need to fit all plants in a 15 foot area and have the lamp in the middle to get a reasonable watts/foot (26) this is still low, but will work.
as far as how it will look, it is indica dom, so it will have broad dark green leafs. Tite internode structure and dense buds. Little strech in flowering and short over all stature. Will probably be branchy. check the breeder est. yield for that stat for I have never grown this strain