1000watt light covers what size tray

I have two different opinions that are quite different.
One guy says 1 light for 4x4 tray or 16 plants.
The guy who posted the thread on here called sea of green says he has one 1000watt light for two 4x4 trays so 32 plants.
How many plants or 4x4 trays does one 1000 watt hps light cover adequately?

It depends on your setup. If you have a flat garden i would say 1000 is good for a 4x4 ideally if you are using a reflector. IF you want to go more advanced and build vertically and use no reflector then a light can light 64 sq feet easily ( 8x8 or 2 4x4). Also depends on if your talkin hps or MH because you dont need much light to veg so you could use a 1000 mh to veg 8x8 but for flower you will likely want more power for good quality fruit. Im by no means an expert but that seems to be the concensus.

Thank you very much. After reading through some of these posts I realize how little info I provided but you answered my question anyway.
Flat garden , reflector, flowering, hps is the set up so it seems 1000 and 4x4 tray is good.
My other friend who is supposedly quite experienced says he runs 2 1000 hps for one 4x8 tray. Does this sound okay as well?
I assume that 2 lights mean more c02 and more cooling so IM not sure if 2x1000 watt hps over one 4x8 tray is better than 1x1000 watt hps over one 4x4 tray.
I am just buying equipment etc and I have tons of room so I can configure anything I want, just need to know what to buy.
Many Thanks for your patience.

Also, oddly enough the guy who did the SOG grow room on this site says he runs 1 1000 watt hps over two 4x4 trays.... so now I have three contrary examples:
1.1000 watt hps for 2 trays 4x4
2.1000 watt hps for 1 tray 4x4
3. 2 x 1000 watt hps for 1 tray 4x8....
Which set up is best. I can buy any one of these combos I just need to know. The set up is hydro and the plant should only be 3 feet (Indica not sativa)