I was under the impression you were going to add rock slowly while it was plumbed in with your clown tank. My thought was that as you added each piece of rock to your new tank, you would have to wait for it to adjust being plumbed in with your clown tank.
It's hard for me to get a read on if you're in a rush again to get this going, or if you're alright with letting it cycle on it's own and then plumb together. I figured that instead of adding dry rock on piece at a time being plumbed in with your clown tank, it might be just as quick to let the tank cycle and then plumb them together. That way everything would be cycled and caught up, and you would have the benefit of a nicely established tank filtering in with it. I don't know which one makes more sense, I was hoping that maybe you would!