Clonig main cola

I have just started another grow with about 20 plants from seed. Unfortunately the grow space has 6 foot ceilings and I am growing hydroponicaly so I will need to top the plants. I would like to take the tops and make them into clones. Not only will this keep the plants height down but it will allow me to fill my growing space closer to a sog style. Although there is a lot of information available on cloning it seems to be tailored towards taking multiple clones from a mother plant and Im wondering if, and how I can go about cloning the main cola.

When is the earliest I would be able to succesfuly cut and clone the main stalk?

How big much should I cut?

I plan on building or buying an aerocloner so I should have a pretty good medium (or lack of) ,on which to clone.

Any advice or experience is appreciated, cheers.

top the plant like you normally would, then clone away.

If your going to chop the main cola your pobably going to only get one clone and thats pretty much the top you just clipped. Now, I am not sure what you other gauys are saying about top "then" clone but by saying this I am sure you mean if you happen to top your plant far down then stem where you surpass several nodes then maybe your going to have possible two or three clones you can take from that. Make sure you cut at a 45 degree angle for max. root growth. Each clone should have at least a node in which is toward the bottom and that way you can cut those and have three rot sites.
Try it, you'll start having some real fun.
Good luck on your grow!