LED's really can't grow much other than low light plants. The Fugeray by Finnex is about the only LED light system that can grow medium light plants but it's pretty costly. What I suggested will save you money as well initially and although in the long run LED's will cost less electricity, they do burn out easily and then are extremely difficult to replace. Just thought I'd let you know
of course you can totally get what you want, I certainly don't mind haha, but definitely research the light first to see if they give out a PAR rating for the light.
But yeah, I love dwarf sag as well! I've actually just ordered my first ones so hopefully I can start growing some myself....not that I need anymore plants >.< but basically I hope to do basically what I suggested to you in my Cube lol at least with the dwarf sag I will be, I've got Quilwort in the back so far doing well but I haven't had it long.