How many LED watts for 2.5+lb per 4x4 tray?

I've researched the internets and haven't came up with the most conclusive results. I did make a previous post asking about two different lights I'm looking into, though I should of asked a more important question, how many LED watts would I realistically need to hit 2.5lb benchmark with a 4x4 aeroflo tray? I'm looking into the Cidly Apollo line.

I'll be running 36 Critical+ Clones (31.5g per plant desired)
2.2 per sq ft
lollipopped
AN Nutes
No CO2 unless temps get above 85
3+ years of success, failures, and most of all, experience.

I'm just changing things up a bit and looking for guidance so I don't spend more than I need to achieve my goal.

I was thinking 2 to 4 of these http://www.alibaba.com/product-gs/511417955/Apollo_16_newest_led_grow_lights.html with a custom spectrum

1200-2400 LED watts with lens....
overkill?

4 of those would probably be about right. Good luck.. There is a sticky so you should probably let this thread go to the wayside

I saw it after the fact, I apologize. Thanks for the insight.