That was my concern. I started these under a cfl and in a starter kit and they popped right up and grew to about 1.5" in the first 2 days. Its crazy that about a week later they are still 1.5-2" tall but the leaves are definitely looking much more developed. Im guessing the intensity of the light will keep them shorter and more full, I have the light at 42" for now hoping to get a little reach out of them. This site has been a great research but also makes me a bit paranoid seeing so many gorgeous and healthy plants. I think my setup is somewhat similar to this thread
https://www.autoflower.org/f52/think-different-autoblueberry-under-mars-ii-700-led-33898.html but I look at those plants and figure im doomed. Haha. Ya ya ya I know. First grow, roll one and relax