more than one light, ideally 4
. You can also use more light than most grows have. PPFD at 10" (or sometimes less in these marketing par maps) is irrelevant. You want to hit the whole canopy with as similar a light level as possible from the tops to the dirt, and that is best done with the light farther from the top of the canopy, which means more watts than is often suggested.
If you don't want multiple lights, a bar design with wide distribution would be my choice. If my 4 diy arrays ever give me grief, a bar setup is likely what I would go for. I would be looking for ~600mmols/m2/sec across the space at no closer than 18" or so. The only issue with a single full sized bar setup is that you can't tailor height to different plants, and being able to do that can help.
I've been out of the market for a while, so have no useful specific recommendations on commercial products. However, if you are into some electrical DIY, you can put together perfectly functional lights for less money. The screwin arrays I use work well:
1. Each light has its own ballast, so ballast failures (even Meanwells go down occasionally) do not cause problems. Worst case, you need to replace a bulb, not a ballast that shut your grow down. The downside is the heat, but I need that anyway since I always have to add heat to my drobe anyway.
2. Spectrum is adjustable by choosing the mix of 5500k and 2700k lights, more of the former for more blue and shorter more compact plants, more of the latter for a bit more stretch. I don't fuss with UV, far red or infrared, I get more nice weed than I need without the fiddle.
3. The four arrays allow height adjustment to each of the 4 corner plants. What I typically do now is just screw all bulbs in and lift the light until I get the ppfd/dli I have in mind from as far away from the canopy as I can. This delivers the most light possible to the lower canopy, given my preferences for light levels at the top of the canopy.
4. If less light is needed than can be achieved by lifting lights, intensity and/or spectrum can be adjusted by unscrewing bulbs.
You could also build your own bar design by ordering strips, but at the cost of depending on ballasts whose failure could mess up a grow, and adjustability of spectrum is not often available except on expensive units. You could make 2 or 4 height adjustable arrays with strips as well if that was a priority.
Electrical DIY is not everyone's cuppa, but if you are up for it, there are advantages worth considering, especially if you want to keep the cost down.
1500$ for 650 watts
i almost did similar once, but ended up gettin a couple lil chiwaineze 120w qb'z instead & they work a treat 
ppp
