Advise on when to start...

Okay so I don't have a camera right now BUT I have seedlings that are about 1/2 - 1". They all are showing their 2nd set of leaves. They were started in RockWool cubes and I'm wondering if now is when I put them into my ebb and flow set up or if I should wait till I see roots coming out the sides?
What about clones? Do you just wait till roots start poking out of the sides?

So then I take it anytime you feel like then...