Thanks for your feedback here, and I find it resonating with my general feelings about this topic.
From what I understand of Socionics, the relationship between types (and especially the quadras) are the linchpin of the typology. In other words, the focus on how specific people/types mesh or don't mesh appears to be core here. While I have wondered why there can't be an alpha type or an alpha type (and why by definition heads in a delta-ish direction, and how goes beta), I also think that the answer probably represent something inherent in how and team up, how and team up, and how and team up (which I may or may not understand perfectly right now).
There is something about the open, receptive, passionate, goofy, fun-loving aspect of alpha that is bringing me to SEI. I am simply not as earthy (by default) as the main delta types (although I can be earthy as a backup style to my more lighthearted alpha preference).
In order of preference, I lean
alpha > delta > beta > gamma
I hope that my logic here is on track in terms of how the Socionics theory (in terms of all IM elements and the 8 functions in their proper order) should be interpreted. Otherwise...it would be back to the drawing board....I hope not.