If you really wanna go down the LED path,Superbright 1000 LED,you could get two for around £110,run them side by side and you should hit good weights ,For very little cost to run ,twin fan in each one ,you would only need a 4inch filter 4 inch inlet.I would just do the one plant ,but scrog it ,or you could do more and flower smaller,but most likely end up with the same weight has doing one.I would say HPS,but in a tent of that size ,it would be a ball ache to get the temps right,for the money your wanting to spend,unless you can get a 600 cool hood ,and decent fans for in and out lets for that price.Or Cool tube ,I used all 3 ,and you won't beat HPS for Weight ,I found the LED produced really good Quality bud ,but In total around 5 Oz dry cured bud ,with a few bits I did not bother weighing.The Mars LED 300 ,produced the most weight and quality wise from the LEDs I tested .Same price range has the Superbright 1000 ,Great lights to start out with .I would like to Run two of the SB1000's at some point ,Double figure weights are easy do able I would say with two of them in that size tent,heat would not be a big issue either.Both are in my Blogs, In the Journal Section .