Going to upgrade to a bigger hps... Need to know how big to go...

So as of current i have a 400w hps with a grow cab thats 2 feet deep, 3 1/2 feet wide, 7 feet tall, im running a 435cfm squirrel cage fan...

My last grow i just did some normal plants, no SOG, Lolipoping, or any other techniques, i used my 400w hps with an additional 260watts of cfl's. This grow i plan to scrog 5 plants and dont want to use any cfls... To many damn cords in the box...

So at first i was just planning to upgrade to a 600w hps but now i think it might just be worth it to go with a 1000 watt... Then again my area might be to small for that much light and it could just be a waste of money on the electric bill...

Whats everyone's opinion on this? Also is 435cfm enough to cool a 1k watt with a cooltube?

with your limited space, I would stick to the 400 watt. its more than enough light to cover 7 square feet. just train your plants to have multiple bud sites, and manage them to have an even canopy 12-16 inches under the 400 watt.
unless you plan on at least doubling your grow area, to 16 sq ft or more, there isnt much point in upgrading.

Thanks for the input. Now that i think about it and really do the math a 1k light would def be to big for the area but dont you think maybe it would be worth it though to upgrade to a 600w hps. I mean from everything ive read ideally you want 10,000 lumens per square foot to maximize your plants intake capacity.. Currently my area is giving me 7857 lumens per square foot which means im not fully utilizing my area. If i upgrade to a 600w i would then be maximizing my area with 12857 lumens per square foot... Yes that is alittle to much but in that case i believe i would be providing more light to more shaded area's of the plants..

Just my 2cents

Any other suggestions