I've never done any formal experimentation, because as a person with no small scientific and engineering background, I realize I don't have the space or the time or the desire to do all that work establishing control groups, precisely measuring everything everywhere to eliminate variation between test batches, etc. Anyone who has failed to take the time to do all these things themselves, has no scientific basis upon which to make any claims.
My training leads me to profoundly doubt any and all claims that contend that this or that disfiguring and mutilating method improves yields. Generally speaking, that which disfigures or mutilates in nature results only in reductions. A person might pinch off half the buds on his tomato plant in order to get ten large, perfect tomatoes. But that reduces the yield of tomato.
I can see how those with tiny little grow spaces might do some laborious training, like LST or SCROG out of necessity. Or pinch to control height, etc. I'm highly skeptical that would result in improved yields based on weight in a controlled scientific experiment, however. I certainly reject the notion that anyone gets an 85% yield increase, as has been claimed. That claim simply defies common sense.
I think maybe some people just have a lot of time on their hands, or perhaps a different relationship with their crops then I do. What I want is not a hobby to bury myself in, all I'm doing is growing one other thing in addition to everything else I grow, like carrots, lettuce, tomato, squash, etc. None of my plants are getting my undivided attention lol, or *that* much effort! I just want the products
So for me, if I found that I could only spare two cubic feet for pot, I wouldn't grow it. I'd find a new place with an extra bedroom, or a remote place for outdoors cultivation. Then it would go like this....lotta light, 3 gal pots, seeds, water...water...water.. ... ... ... harvest.
As for the "Special Grow Mighty God Bloom 2000" for $137 a pint, all I can say is bwahahahahaah!
That stuff is the same as every other batch of overpriced accessories that springs up anytime anything becomes a widespread fad. Today, pot is in "fad phase" amongst them English, and now we have the snake-oil folks looking to get rich off it.
You can purchase everything you actually need, at Home Depot, and get change back from a $20.