It depends a lot on climate, watering frequency (manual or hydro) and coco or soil choice (soil being harder to get right = slower growth almost guaranteed). Many things can slow down growth, cold being the most obvious, along with under watering. Plants can also stretch a lot from seedling if light intensity is too low, makes long stems with large node spacing. Plant count is the next major influence, in a 4x4, 4 plants will take longer to top and train out than 6 plants then 8 plants, etc etc.
With an optimum environment and 4 plants being topped or trained in a 4x4, 8 weeks should be enough in coco, including rooting. Hydro might get away with it in 6, not sure. Some strains do stretch or have tighter nodes than others, so this can add or take away a week or two.
Using 8 plants, you can be ready to flip in 5 to 6 weeks. More plants than that will obviously lower it, to the point where a 2 week veg (rooting aside) is necessary to not over grow space, but that's getting into real sog, it's not logistically easy.
If you don't have optimal settings, you would technically need to veg longer to make up for it.. but in reality most people won't have the patience to veg past 8 weeks if not on a perpetual. Due to less than optimal veg environment you will naturally yield less, even more so since the flower environment is also likely to be just as sub-optimal.
On a perpetual, you are locked into the flower time if taking cuttings from cuttings (9 week strain). This means roughly 1 to 2 weeks max in rooting, and then a further 9 weeks of veg (1 week includes harvest and turn around time). That's way more veg than is necessary, however, it saves the need to keep mothers. Using multiple mothers is just not worth it in the end, that space could be flowering space. Unless you have some insanely rare strain that people will pay more for, or you just love to death, theres no point IMO. There is plenty of good strains out there now, only real difference is well cared for weed, or not. What you do instead, is top cutting plants regularly, cut them completely in half at week 4, and then again at week 7 if needed. It sounds wasteful but all the alternatives to reduce overgrowth in veg are more costly, waste space, effect root development, or worse for the plants vigour. Sorry I just cba to go into all that.
