I wouldnt' think 250w would be enough to grow eight plants, even Lowryder. You would be better off getting a lighting system off ebay etc. rather than an agricultural website.

I dont think you could grow that many in that size room, what with the room for the pot (the root system even for a stout plant I suppose is big).

Do you have air inlets/outlets? Do you have a filter? A fan blowing on the plants lowers the temp and helps the stems develop. Although moving air also lowers lumens