Aye and there's the rub. The "fascia" and the jin/kokyu are interdependent, but they work as a whole in the full banana. In the not-so-full banana breath is just a conditioner of fascia and fascia is an adjunct to the the process (including dantien/hara usage). So 'various breath methods' won't really tell the story by itself, but you don't really get full internal power without practicing correct breath methods. And they take a while to show results.
OK. Then let's define "correct" breathing methods. What makes a method "correct"? What's the difference between said correct method and someone doing, say sanchin and/or tensho from a Goju-ryu tradition (as an example)?