New light search...chime in ;-)

I'm trying to decide what type of light to get any suggestions would be greatly appreciated...here's what I have so far

room is 6x5 so 30sq feet if I go with 50 per foot I'm lookin at 1500w is that how much I should go with even if I use digital?

I'm thinking either 600w or 1000w ballast a wide spec horti bulb and a parabolic reflector possibly 2 ballasts if needed I'm looking to use the entire space for growing but not all will be mj

I've been looking at the blue lumatek digital ballasts with the RF shielding etc does anyone have any experience with these...I've heard they can interfere with radio signals(cell phones, radio, satelite etc) anyone know this to be true or not? lumateks site says this isn't a concern...

I've also read that digitals give off way more light like a 600w mag coil will cost like 675w to run and give less than 600 to the bulb where the digitals will give almost all 600 drawn to the bulb

I've also read that a 600 will perform just a bit worse than a 1000 mag ballast but if you use the lumatek information of max 30% improvement that would mean a 600 would perform a bit better than 750 which is definately worth it but not really close to a 1k

I'm not sure how close you can get a light to the plants but I'm pretty sure the 1000 would have to be further away anyone know how close you can get a 1k to the plants before they fry?

Is there a major benefit from 120v to 240v? it looks like 240v might be a bit more efficient giving a tad more light for the electric draw but again maybe someone has experience

Heat is no concern as the room is currently a little cold anyway and ventilation will easily keep temps within range