I want to relate my experience with chakras.
Several years ago, I did some practices from this book
. I had kundalini awakening experiences right away and it was frightening. I quit after a paralyzing force pinned me down and in my mind, I imagined a blue thick beam of light entering my back at the heart chakra. One other thing happened before that: a sensation of being pulled up by a hook in my naval chakra. Fellow Dharma Wheeler Red Dust and I were recently having a conversation about her spontaneous kundalini awakening and when I did some Googling, I found that several people were trying to figure out how to deal with these "hook" sensations that could actually be quite painful and appeared to be constantly pulling energy out through the top of the head. One person speculated that they were karmic links when the idea popped in his head that these were "chains" and the kundalini was getting rid of them. NOW I DON'T KNOW ABOUT THAT and I'm certainly not saying that's what is happening. That was just one guy's belief about what he was experiencing. But, reading about these people trying to get this problem under control convinced me that the hook sensation I experienced was the beginning of something and I am glad I stopped when I did.
The other thing I want to mention is the book linked shows all the same kumbhaka holds to activiate the kundalini as in Namkhai Norbu's Yantra Yoga book, but the general theory or attitude behind the practice is completely different. And it uses the hindu 7-chakra system.
I have come to believe that since Namkhai Norbu's teaching is considered "safe" that perhaps, as with the bodhicitta intent in meditation, so too the conceptual underpinnings behind working with the chakras is what makes them much more safe to work with in Namkhai Norbu's teaching.
All of this is to say I think its not a good idea to try to mix and match systems thinking that because they work with chakras they will have the same result. Not that you were doing that, but I'm awake and thought I'd add my 2 cents.
"Use what seems like poison as medicine. We can use our personal suffering as the path to compassion for all beings." Pema Chodron