Aloha Sean,
There are countless way to do the Small Universe/ microcosmic orbit. Some stop in less locations, some more. Others have sound, and still others only visualization. Some you have to stop at all 100+ points and not miss one, or start over.
KISS (Keep It Simple Sean)
Think of it as an area that the energy/light is going into and the excess is then leaving from.
For example:
Navel area (behind)
Bladder area (think area - there is a lot going on in that area)
Bottom of the torso area (yes, Hui Yin and the area around it)
Tailbone (think of the whole area included in the tailbone)
Lower back (think of the area above the tailbone and below the kidney area - take a look at an anatomy cart of the body with organs.
Spinal Cord (think the area around the C7 vertebrae)
Breathing: Once a person has the exercises on meditations down pat, they can integrate the reverse breathing. Most times I recommend one do it for the first three breaths and let it go for the remainder. That way they can practice it correctly a couple times, to let teh bosy experience it, and not be in their heads about their breathing "right" during the work. After a while in their training, they may notice they're doing it naturally.
The version of the small universe Chunyi teaches in Level One is the Small Universe he teaches in Level Four. As you develop the 6 keys to success (P.26 and the 3 Secrets(P.19), the more the meditation is "advanced."
Much Love, Shawn