looking great bro.
if you just switched to flower, your going to see some amazing growth rates over the next couple weeks.
as they get bigger, they'll start to encroach on each others space. you'll know how far to spread them to get the most intense light you can with still even coverage just by looking at them and moving them around a bit. by the time they're done stretching they'll be wall to wall solid in your tent bro. . . .what is it again 4x4?
right now, that you can still have them close, 10" is cool to blast them with light, but honestly, i doubt their growth rate has increased much (compared to say 16-18" above canopy) unless you really have all of your variables totally nailed, and use co2, and the genetics have more to give. . . when they get bigger and you have them spread out you'll need to raise your light to say 16-18 inches above the canopy anyways to make sure that you are throwing your light as evenly as possible all the way to the edge.
in fact, i think i would rearrange them now if it were my decision. you'd have to raise the light a bit probably, but when they grow out, like i said before, they start to encroach on each others space, and due to lack of light penetration under the canopy, they don't grow too far into each other.
if you spaced them out now, they will find these barriers naturally. it is my opinion that as evenly spaced on the floor plan as possible is usually the best. . . with fine tuning as you go.
the only downside to this would be slightly less light, but trust me bro, with 1000w showering down on them, even at 24" you are going to see some wicked growth on these bad ass mommas. . . more clearly, you could go to that distance without any real noticeable decrease in growth rate from what you're getting now.
but, just trying to help, your doin a nice job so far.