I use 7 liters and I can grow 2m plants in it.
For a rooting hormone I use a local stuff called Hormonile 3, but you can buy Clonex, I've heard it works great. Its a jel.
You will want to clone branches that will not reach enough light anyway, 3 nodes high.
I got a tutorial on that linked in my signature.
What are your plans for it?
Mhhh Good question should it ..why isn't it tied down yet?