looks like a good way to start out. (In before flamers
)
The only thing I would see with that system is that the pots don't look like they can be moved further away from each other as the plant grows to give them more room. Plan on them tripling in size when you flip them from veg to flower. I think it would be a good start, I have never grown with an led so what area a 300w would cover idk... I think led would be better than cfl lights tho.
As long as you keep them tied down (lst) or scrog you could train them to grow low and increase yields by opening more bud sites up to the light.
More plants isn't exactly better. For example: I had 3 plants under a 600w hps in a 4x4 room and yielded a little over 600 grams. The next grow I put 4 plants, same strain in a scrog aerponics system same as before, and only harvested 448g of sellable buds, but a ridiculous amount of stringy buds that I made into hash... Which I was ok with having a few extra oz of bho lol. The reason being is that the extra plant I squeezed in there overshadowed and crowded the other plants out and blocked light from penetrating down into the canopy.
Point being I think 2 plants scrog in that system would work great, and if you can put more in after the first grow then do it! Northern lights stays pretty small ime so maybe all four would work... That might be something you have to play with to find the honey spot.
Just remember they will double or triple in size when you switch them so plan for that and you'll be ok