Just for a refrence, I use short veg times. Even the 3 plants for a pound under my 600w was only 5 weeks old from the day it was cut. But this is also very strain dependent. On that same grow, I has 6 very small(6-8") clones of the same strain that were only 2.5 weeks old from cut and they only yielded 6 less grams. here is my current grow of Blue Kush so you can see what is still possible if you do little clones of the right strain. THis shit is coming down this weekend.
Day 3 of flower on this run...
And this is them at day 52 of 12/12
Keep in mind, if you flower clones this small, it usually takes the flower stretch 3 weeks to finish, but it takes me from plants barely touching the screen to all of the branches sticking over a foot through it and filling the whole thing out.