Question for clone growers

I see the majority of people who grow from clones tend to only do a short veg, a week or 2 and some even go 12/12 as soon as the roots hit the water. How big do the plants get when switched to 12/12?

I have been flowereing my seed sprouts after like 8 weeks of veg but now that i have locked in a few strains i want to keep those mothers and just use the clones. I use the scrog in my tent and while i have only been flowering 3 plants and they do not nearly fill up my screen. I am curious cause now that i want to just use clones i am wondering how many clones could i use to really be able to fill up the screen to have a good scrog.

How much bud does clones usually harvest? I have 20 clones that are being rooted now but i dont know if thats 2 many or if i need more. My tent is 40x40x79.

Thanks for the feedback!

You can veg clones as long or as short as needed. If you're going for a SOG, most folks only veg for a couple of weeks. I veg until my plants are about 12-16" tall. I also top most of my strains, because I'm going for a few bushy plants, not a bunch of single colas. I flower in a 4.5x4.5x6.5 grow tent, so I usually flower six bushy plants at a time. They pretty much fill the space.