2X to 3x really is a good measuring stick. My dresser I use is only about 3 feet tall. My first grow was tiny as I didn't really know what I was doing.
This time i was a little more aggressive with the LST (Low stress training) and it gave me more room..... the grow is in the basement (dirt) So I actually dug down in the sand to give me even more room! I am kickin around diggin even deeper and just putting dirt in the hole. I am not that concerned with portability, I suppose.
I started with two plants and started flowering early because my plant showed hairs a lot earlier then I expected. You can flower whenever you want, but if you are growing from seed it will likely take longer.
The reason your clone showed hairs so early is because it keeps the age of the plant with it when you clone it. So even though it may only been cloned for a short time, you might as well consider the age of the mother plant.
I have seen some pics of buds 3 inches tall that were taken from a mother.... looked like a small christmas tree.
it really is amazing some of the things you can do.