36 plants in edd/flow under 4 400watt hps

Here is my setup, I got 5x10 tent, in the tent are 6 2x3 bins filled with clay pebbles. I want to grow 6 plants per bin. So a total of 36 plants. I have 3 hoods, the end hoods have a single 400 HPS, the middle have one 400 HPS and a 360 HPS conversion bulb MH to HPS. A total of 1560 Watt. I'm getting worried this light might not be enough. Should I switch the end lights to 1000 watt each? and keep the middle hood with 750 watt. Any suggestions/comments would be greatly appreciated.

i think im using the same 2/3 bins that you are as for lights i think upping them to 1000w would definatly help and if its in your budget go for it but i think you could get by fine with those lights. and just a heads up filling those bins with clay pebbles holds too much moisture for me and im in a dry climate might want to think of using pots with clay in them.

I will grow my first crop using this method, if I get too much humidity i will put them in buckets with clay