The stretch is a myth...what do you mean exactly?
It is very strain dependant. And you can help tame it by playing with lighting K during transition but some plants are stretchy.
I have a few that i put in 10 inches on top of the pot that hit 36 inches routinely. Some indicas that dont stretch 50%
Temp difference, light cycle timing (in veg 24-0 stretches less than 18-6) so many variables.
Grow an Ace seeds sativa leaner and tell me its a myth...
I veg with a 4200 CMH and then transition with a 4k area in bloom (boards and strips). Then it transitions to the 3k and far reds area.
Does it work...i have no idea. A lot of the plants do not cooperate regardless of what you do. I just ensure i put them in bloom at no higher than 16 inches to max out under my 5 foot 8 clearance. But if you grow a strain enough you know it is a 50% stretcher so you can veg it longer etc.