This depends on a number of factors, plant numbers, grow space, light intensity etc.
With your current light setup tall plants are completely undesirable you need plants with many tops that are short.
If you have 6 indentical square pots in the flower cab, with 25watts per square foot, I'd be looking at 3 weeks veg then flipping to flowering. With 4 plants I would lst and veg for 4 weeks at a push then flower.
I rarely veg over 20-25 days, the plants double/triple in size when you change the light cycle so factor this in too
If they're healthy and vibrant they usually double or triple in size.
Have you thought about using a screen ie scrog style, it's a good way to control height and achieve an even canopy. Particularly useful when you're using low wattages.
They can be small like this, individual ones are a good option for your space (not my pics) you can make the screens out of coat hangers and twist ties or chicken wire etc The idea is to create an even canopy at a set distance from the lights to maximise the efficiency of your bulbs 💡