I do this regularly as my room is very limited. So, I wait until the plant show's sex and stretches a bit to get cuttings long enough to be sure one node is under the soil.
This time however, I waited until the plant was 3wks or more into flower.. like yourself, her first few cuttings died and I really wanted to save her, so I took 10 more. If the flowering heads are a bit heavy, I trim them down as far as possible, plus it helps it revert back to veg growing.
Obviously it is not the ideal way to do things, some say you should wait for a plant to develop at least 2mos. But, I've had great luck doing this for a few years now and I flip my plants into flowering at day 10.. Yup, I try to defy all the odds I guess..:cool0041:
Here is my Agent Orange babies I took just 3 days ago from the plant well into flowering.
I believe this is where a true F1 comes into play. They seem to show much more vigor in their growth with fewer health issues and less variance. F2's seem to take a bit longer to root.
The 2 like this are going to a hydro buddy who needs some better meds.