Little Walter's keying

[Tfine@xxxxxxx]

I'm kind of new to this list and to harp playing in general, so please excuse
what may seem like some obvious questions.  That said, I hope to pick some
expert brains here as to the following:  I am pretty much a self-taught harp
player.  I have learned mainly by playing along to blues CDs and practice,
practice, practice.  I have also read a book or two, which helped alot with
theory and such.

My favorite harp player is Little Walter.  I love playing along with him (and
usually being left long in the dust).  I want to know if anyone can tell me
what key and types of harps he's playing on the songs from his "Essential" CD
(listed below).  What I'm looking for is, for instance, is Mean Old World
played on an A diatonic?  I learned to play on a Hohner A Blues Harp and have
since bought MS Blues Harps in C and E.  I'm trying to figure out which keys
to get next.  I will probably expand my brand selection based on what I've
read here.

Songs:
Juke
Can't Hold Out Much Longer
Boogie
Blue Midnight (Alt. take)
Mean Old World
Sad Hours
Don't Need No Horse
Tell Me Mama
Off The Wall
Quarter To Twelve
Blues With A Feeling
Too Late
Fast Boogie
Lights Out
Fast Large One
You're So Fine
Oh Baby
I Got To Find My Baby
Last Night (first version)
You Better Watch Yourself
Mellow Down Easy
My Babe
Roller Coaster
Little Girl
Hate To See You Go
Boom, Boom Out Goes The Lights
It Ain't Right
It's Too Late Brother
Just A Feeling
Ah'w Baby
I've Had My Fun (alternate take)
Confessin The Blues
Key To The Highway
Walkin' On
You Gonna Be Sorry (Someday Baby)
Crazy Mixed Up World
Worried Life
Everything's Gonna Be Alright
Back Track
Blue And Lonesome
I Don't Play
As Long As I Have You
Just Your Fool
Up The Line
Southern Feeling
Dead Presidents

THANKS EVERYONE!  Sorry for the length....

Tom Fine