I'd say I'm using close enough, I run EB's at different currents...
Distance varies a lot but I'd start flowering with maybe 20-40cm, and later into flowering I try to keep most of my tops in the 10-20cm range. the few highest tops are at about 5cm from the lights.
This is with a system that has a little more punch then yours, now I have 550w in a 4x4. Earlier I was running 480w, and everything seemed similar.