Hi Migangelo.
Yes, Chiong is very passionate about his discovery and does tend to let everyone know that he thinks he is doing it right and others are doing it wrong.
I too tried to learn more about his 'discovery' without buying the book, but he doesn't let anything slip. If his book had been in hard copy I might have talked myself into buying it, but I have a strong aversion for paying anything for digital information.
On the subject of engaging glutes however, I had a running gait analysis done by a professional lower body biomechanic. He pointed out that my glutes were weak and not doing anything, and that I was tensing my quads and they were doing all the work (and failing, hence my stamina problems)
His recommendation was to do glute strengthening exercises and calf and quad stretches, and said that when my glutes get stronger, they would engage naturally.
I have been following his advice for a number of weeks now, and my legs and lower body do feel like they are much stronger, my quads no longer hurt or give up, and I have broken my PB record twice recently! (Though there were other changes in my medical conditions around the same time, so there are other factors involved in my recent performance improvements.)
I read an interesting article about the loss of use of our glutes recently. I will have to go and find it and get back to you.
I hope this helps
Good luck!