ok here is a simple diagram took me 5 mins to make so its not that good. but it shows my thoughts at least I think it does anyways.

The basic thought in mind want to light the inner fan leaves where other light is shaded my larger fan leaves from the tops. A typical hung HPS only shines light downward and reflects off the walls floors and or anything else that you are using to reflect. So i am certain that the depreciated reflected light would not be penetrating the inter leaves or the ones under shade I should say. The idea would be to put the light right at the source of the shaded area and light up the leaves that are shaded. I have no test available because I have not built any lighting systems from LED but I have been reading a load on LEDs and thought this might be something to check out.