Yeah, I would say identifying one's enneagram is just as much as a pain as finding MBTI type. They all somewhat go together. Like this...
Mbti/Jung=environmental focuses
Enneagram=How the Ego protects itself
Instinctual Variants=What you focus on for survival.
That said, How does your ego protect itself? For a three, there is a drive be impressive, successful, or to stand out because that's where it's value is, within the image triad. It fears being worthless, hence tries to stand out through "success" to garner worth.
The six is of the thinking triad which goal is subjugate "thought" (negative ones of course). Triads are similar like Mbti, there being a directional focus (introversion/extroversion). The 5 is an introvert, mentally preparing for the external world. The 7 is the extrovert, distracting itself to avoid unpleasant thoughts of within or pain. The 6 is somewhat of both worlds, an ambivert. The 6 fears like the 5, what the external world may bring. Yet has the need like a 7 to distract itself from such thoughts. That is why the 6 is tied with the notion of groups or establishments. Such things ease the 6. Woah, long-winded. Did I just make it harder to understand than necessary?
Basic fear:
type 1- of being bad, imbalanced, defective, corrupt
type 2- Of being unloved
type 3- of being worthless
type 4- of having no identity or significance
type 5- of being helpless, incompetent, or incapable
type 6-of being without support or guidance
type 7- of being trapped in pain and deprivation
type 8- of being harmed, controlled, and violated
type 9- of loss, separation, and fragmentation
Basic desire:
type 1- to be good, to have integrity
type 2-to feel love
type 3-to feel valuable
type 4- to be themselves
type 5- to be capable and competent
type 6- to have guidance and support
type 7- to be satisfied and content
type 8- to protect themselves
type 9- peace of mind and wholeness
You could be a 3w4 6w7 xwx (That's my guess for your tritype)