So pending height in future I can flip after 6 weeks... That's good to know as I have had a close friend (who apparently knows his shit) tell me to wait for the 10-12 week mark. then I have come on here and done some reading,I cant say I have seen anyone veg that long. I know with my current plant she has needed the extra time due to my lack a green thumb so to say
Try not to focus so much on when.
You will have to judge based on height and observed growth rates over time.
People say 2-3x stretch.
So with your final planned pot size.
Put them in the room and measure from the top of said pots to the maximum vertical distance with the planned buffer for heat between the lights and canopy.
Once total vertical height is measured either divide it by 2 to get your ideal flowering height for a slow growing plant.
Or divide by 3 for ideal height for a fast growing plant.
You could also just err on the side of 3x growth to be on the side of caution.
For example I have "30 of height from pot tops to the maximum distance with "8 buffer between light and canopy at max height.
4 of them are slow growers and 1 is a stretcher. So I started flowering at "10 height to be safe.
They actually hit planned height on day 2 of flower. I wanted to be safe.