I just did! There is no secret. Regarding the whole plant cola's, that is mostly a result of my 12/12 from seed background...putting plants into flower when they are like 3 or 4 inches tall. That is what you're seeing here for 3/4's of the plants I have right now. I chose this method simply because I'm trying to experience as many different genetic packages as I can as quickly as I can.
That said, this is an absolutely viable method for larger scale production *if* you can make your own seeds or produce your own clones. Each of the plants will not yield an impressive amount, but when you can fit (4) per square foot, it starts to make you wonder a bit.