I'm a complete novice so this is only my "artistic" opinion, which is identical to having an @-hole (we all have one and they all stink)
So, I prefer the semi-staged (not completely random) look. Where by positioning them close together but not too close you create varying dimension with positive and negative space.
Here is what I just created last week.
On the right is my attempt at an Iwagumi-ish scape. Despite knowing it could be better I'm quite happy with it.
So for your rocks, if they were mine, I would place them closer together in "mountainous" arrangement and then leave some negative space on one side or the other. Or build the mountain in the center and have negative space on either side. Just some thoughts! Have fun!!