LEDs are very directional in their light output, which has advantages and disadvantages. When you want light in a specific spot and not somewhere else, it's great. When you want to spread your light out more omni-directionally or spread it over a larger area, that's an issue. The exception is using LEDs in a volumetric optic. Certain lights do this to send the light out omnidirectionally (and to create broad light spectra that bare LEDs can't do). There are 11W screw-in bulbs and 155W fixtures, so it fits what you're describing of more, lower powered fixtures, while also distributing the light more broadly to penetrate and light more plant surfaces.I've found this common on all the LED's I have tested so far, they have excellent intensity just below the light (within the dimensions of the light) but more than 1' outside the direct overhead lighting, the lighting drops off quite a bit. I have found with LED it seems that more panels with less wattage is better than 1 large panel with lots of wattage. All of my different brands of LED do this, some carry the footprint better than others but they all drop off quite a big outside of a 2'x2' area for the most part. I think you are on the right track with more lower wattage lights to help extend the footprint.