Newbie - Identifying Morgan Obverse And Reverse Hubs, Types And Varieties

HI,

I'm learning about VAMs and varieties for my Morgan collection. And there's one thing I'm not clear about...

When Mr. Van Allen (ref: Vamworld website) says:

Obverse I = Thin letters in LIBERTY, evenly divided rear portion of ear.
Obverse I1 = Incused designer's initial.
Obverse I2 = Raised designer's initial M with two parallel vertical bars.
(...)

Does he mean that Obverse I1 and Obverse I2 both have "Thin letters in LIBERTY, evenly divided rear portion of ear" as well

Like for the Reverse, he says:
Reverse A = Eight tail feathers.
Reverse A1 = Raised eagle's beak.
Reverse A2/A1 =Hooked eagle's beak with lower beak and tongue usually doubled. Top arrow head and shaft doubled.

Does he mean that sub-types A1 and A2/A1 both have 8 tail feathers too

I thought so at first, but sometimes the info is contradictory, for example:

Reverse A = eight tail feathers
and
Reverse B/A (a sub-type of Reverse A) = seven tail feathers with portions of eight tail feathers usually showing below seven tail feathers (...)

Also, for the obverse, he says "hairlines more pronounced". Does he mean "hairline is more pronounced" or "hair lines are more pronounced"

Help?

(I know, I know, I will eventually buy the encyclopedia (in a couple of months), but I just trying to organise/understand the basics for the moment.)