I would go with 25 plants per light at the most.
20 is the normal number for a sea of green with 1 1000 watt HPS.
But 50 with 2 1000 watters will work great.
Get aircooled hoods.
Because 2 lights can make a huge heat wave in your grow room.

I plan on doing the same eventually.
I'll be doing a perpetual harvest every month.
With 2 1000 watt HPS lights.
And 20 plants per light.
Jdog7000 Reviewed by Jdog7000 on . New grow room 10' x 7' Hi all, im going to set up a new grow room, the room is 7' x 10' but the area i'm going to use to grow is 6' x 8' cos i'l need a little room to work in i was hoping to have 56 plants in 10 inch round pots would this be ok under 2 x 1000 watt hps's? Thank's. PEACE TO ALL! Rating: 5