You do have some lead time......if that's the right way to put it. When you flip, new leaf/branch growth doesn't come to a halt that day. It's not ALL stretch. Over that first week there's still some growth and filling in while the plant figures out what's going on. So as we defoliate near the end of veg, we can take this into account.
Most experimenting we leave to others, science.......we don't tend to want to play around with the unknown. But something I plan on doing is a gradual flip. 12/12 is actually very abrupt for almost all varieties. In most regions, and I can only speak for most of the US......not northern Alaska, or the Florida Keys.......certainly not Hawaii or Thailand.....but in the majority of the US, 12/12 doesn't happen until when? November? Why are we flipping from June to November in one day?
What if we flipped to 14/10 to start? For that matter, what if we did 14/10 until harvest, but that's another experiment......
14/10 for 30 days, 13/11 for 30 days, 12/12 until harvest. Maybe even 11/13 to finish.
If 14/10 to start gives a more gradual flip, maybe it gives us more time to defoliate, and allows the plant more time to fill in.....
"You defoliated too much!"
"Don't worry, it will fill in very well...."