Supplemental Light?

Im on day 6 of flower. I have 2 Mars hydro MZ 300 60watt LED lights going. Was thinking about adding a Sansi 36 watt LED. 2x2 grow space, 3 plants in 3 gal pots. Is it necessary is the most important question?

More light more good.

You can squeeze by with 120w led but it's not optimal, the extra 36w would help.

Id get the 36w light. Thats 156w, and almost 40w sq/ft, which is optimal. I would always try and get 40w-sq/ft. No less, than 35, but it has to be with the best diodes ect.