its possible from what ive read, but ive also read that the plant will not actually flower until its mature. howerver thats reading and not doing, try anything once.
also Ive read that many of the landrace strains are recomended to start 12 12 because they arent bred to small spaces. so dont beat yourself up and let your freak flag fly Man.
Good luck and happy growing. Oh and the 300 w will be fine just keep her close.