I simply started tying them off a little late. Four of the six are being reared this way while the other two are stouter and shorter. Overall, they seem ready to go into 12/12 but in order to not have lopsided plants, I believe I will have to continue with 2-4 more anchorings. The interior growth, in some cases, seems prolific, as well, and this also makes me wonder about the huge fan leaves that are actually blocking light, near the top of the plant, so that visible, dense undergrowth is being denied light. Is it okay to prune a couple of leaves per plant, 10-14 days before going into 12/12, so that these areas might come closer to their potential? Thanks soooooooooooo much in advance, and this will not be the end of my gratitude... *
To answer you question, yes it is ok to LST up to about three weeks into flowering. I would not recommend removing fan leaves to get light to lower sections of your plant. Healthy fan leafs do not block light, but absorb light and turn it to energy. If you did remove them on a 4' plant your lower leafs would only get at little as 12% of the light that would have been received from your upper fan leaves, via the inverse square ratio of light.
I LST'd AND adjusted the scrog up until 3 weeks into flowering with no problems. I tucked as many fan leaves as I could and cut about 1/3 of the tips off of ones that were blocking sites. I think I did alright for my first trip.