Considering the sun in many many times brighter nothing indoors is overkill light wise, the more light the better as long as your temps are in check and all other needs are met like CO2, water, nutes, root space, etc. Usually indoors lack of CO2 is the limiting growth factor. (other than low light) Growth rates can easily double with CO2, yields go way up as well.

15 plants get big very fast under 1000 watts of anything, hope you have the space! Let's see pics! :jointsmile: :thumbsup: