Yes i have done indica that apparntly stay squat i no sum will vary in phenos being s1 seeds was just a rough idea as the last lot i done were stretchy as fuckHi,
without knowing the genetics and how they grow, I would say to be safe you will want to be around 80mm when you flip. Once stretch is complete you should be close to the 120-150mm range I think.
obv some strains are crazy stretchers and others not so much, so it would be very dependent on what your growing.
What distance u suggest for 600mh abiut 30-45cm away from canopy?Stretching can be caused from light distance between plant and light is too much/far so the plant stretches to get closer to the light.
Some say the blue light spectrum helps reduce stretching as well.
Lastly it is sometimes genetics...I usually go by 50-75% taller after 12:12 switch...so for 120-150 I'd flip @ 80-100.
Don't forget you can always LST and supercrop to keep heights in check too.
Best of luck.