Depends on how long your going to veg, how big you want the plants to get...
Expect to transplant them again after about 2 weeks of flowering...
dont think they'll be floweringand they will be mothers if that helps.
4 foot for a veg/mother room is fine (if floros and not HID). Once they hit that 'too tall' size, they are getting chopped down for clones and allowed to grow back.Minus your height of your light, light distance and height of your pots. Which will end up not being alot of room...
What are the specifics for your grow? lights, # of plants, growroom, nutes