Hey Johnny, Garden Knowm takes his clones four weeks into flowering and there was a thread about this not real long ago. BUT, he was forcing flowering early, like under a foot of height, this is before it would have reached veggetative maturity. That coupled with the lower nigtrogen content of the bloom nutes make this a viable option. At four weeks of flowering they are mpore like two weeks into flowering as far as sexual maturity is concerned, they won't start showing sex until just about that time. I have some plants that have been in flowering for just a little less than a week and the males are already starting to show their sex.
I have taken clones from plants that were flowering for 8 weeks successfully, I did it with 40 of them at once. It took me about three months to get them back to vegging so I could put them in flowering. Can it be done, yes. Would it be quicker to order and plant seeds? yes. VV