Beale,
"As if it had three separate segments." I know exactly what you're saying, been there on over 500 attempts, and this same "perplexity" is also present in C1. "A key," is what is written and I also believe the pamphlet is that key. As for C1, it is my personal feeling at this time that C1 has been safeguarded by at least two different methods, possibly three? However, and this is just my own belief at present based on my own research and decoding efforts, I do not believe we will find these methods to be overly complicated once the correct "key application" is finally discovered. (I have my reasons for believing this.) Of special interest is the "Gillogly Strings" as it is also my belief that they are there with sound reason. I hate to keep going back to this but I believe it is extremely important to remember, "the DOI only works on C2 if we use the pamphlet version," a circumstance that the "true author/authors had to be aware of." So with this in mind let me pose this question; "which would be easier to keep track of and to send, one key applied three ways, or three separate keys with each being applied differently?" At present I hold little doubt that the pamphlet is indeed a package deal. Suggestion; take what you already know about the "straight to the point" attitude of the cipher writer/writers and then think about all the possible "vowel arrangements" that a proper language use can produce. If your attempts produce incorrect vowel arrangements then your attempt is also wrong. Now consider the "Gillogly Strings" again. Am I making any sense?
I did "click on it"... nothing there... 
