How early for clones/flowering?

I want to mainline my plants. I know this is an advanced technique and im new but i wanna do it.

My question is, when i take the 5th top off, can i use that to clone/flower to determine sex or do i have to wait until a certain point?

http://www.growweedeasy.com/main-lining-technique-nugbuckets

Nugbuckets will teach you everything you need to know.

Good luck friend :3

I have had that bookmarked for a while now. My question is not about mainlining. Its about cloning and flowering.

Yes you can do what described. Get the clone established a bit before going to 12-12 with it.

If you can get it to root like any other clone you can start flowering it virtually immediately to determine the sex of the parent plant.