400 or 1000 watt MH?

OK so im 2 weeks into flowering and my HPS ballast died out on me. I only have MH to fall back on. I have 6 plants. Heres the question; Would I benefit more from the 1000 watt versus the 400 watt? OR should I just use the 400 because its cheaper and I wouldnt notice much difference if I used the 1000? Ive never fruited with MH so what can I look forward to?

Thank you in advance

-LoGiK

PSQ
This ballast for my 1000 watt states on the side (copper lighting) 0-450 watts hg,hps,mh and 1000 watt hg, hps, mh. Whats the chances this will fire an HPS?

If you can handle the heat and have the height than absolutely use the 1000 watter
The more the light the better

yeah, the only reason to use less light in bloom would be to prevent heat. The more light in bloom the better, larger fruits.

go with the 1000 aslong as you can get heat out from between the light and the plants and have a good circulation of air running through

Thank you fellas wiring it up now!