I don’t practice with Tarrant Roshi, nor with PZI. Years ago I read a few articles he wrote and watched a video or two. And he was once a visiting teacher at the non-sectarian Buddhist sangha that I attended. As I noted, I received his book as a gift.
Regarding Tarrant Roshi, “. . . he passed his first koans with Korean teacher Seung Sahn. He studied with Robert Aitken in Hawaii for 9 years and was Aitken’s first dharma heir. He also did advanced koan work with Koun Yamada.” So for those who follow his practice methods and teaching, they are not practicing “according to one's own preferences.”
Regarding his approach to koans,
Although his training was originally in what was essentially still the medieval koan system, Tarrant has spent many years exploring how koans are pertinent to people living in the modern world. He holds koan seminars where people of all levels of experience are welcomed and a collaborative culture is encouraged. Pacific Zen Institute’s program of Koan small groups and salons allow people to study koans together in an ongoing way. He teaches koans as doorways available to anyone, not only for advanced practitioners.
Regarding his approach to meditation, here’s a short explanation:
Meditation can be as complicated as you want to make it, but here’s a move in the other direction:
1. Pay attention to whatever you notice (inside or outside yourself, it doesn’t matter) without thinking it’s good or bad, pleasant or unpleasant, wise or stupid, worthy or unworthy.
2. Actually there’s only one step. That’s it.
3. Sometimes the word “curiosity” will help you.
https://www.pacificzen.org/meditation/
But there’s more detailed instructions on sitting meditation (also, walking meditation) on the link.
Reiun has quoted the website accurately (“mysterious and unpredictable healing power.”), but he left out some of the accompanying explanation.
Here is how Tarrant Roshi defines “mysterious”,
By mysterious, I mean that while the effect of meditation is more or less as advertised, you are on a journey that does not reveal all its features at once, and even the destination is uncertain.
Regarding healing, he says:
Meditation is a project of healing, of putting ourselves and the world into harmony with the flow of life. As we integrate meditation more and more into our culture, it is coming to seem natural that the healing of our states of mind is the beginning of kindness and imagination and making a successful culture. I’m interested in the question, “What are the essentials of the meditation path as a basis for this healing—healing of both person and culture?”
—John Tarrant
So, while Tarrant Roshi is not a traditionalist, neither is he outside of the Zen tradition.
“Enlightenment means to see what harm you are involved in and to renounce it.” David Brazier, The New Buddhism
“The most straightforward advice on awakening enlightened mind is this: practice not causing harm to anyone—yourself or others—and every day, do what you can to be helpful.” Pema Chodron, “What to Do When the Going Gets Rough”