Contraction Controvesy

I like alliteration. I don't consider it the high point of fine literature, but it's fun and easy to do.

Anyway. For some reason I was considering contraction pairs. "it is" becomes "it's", and "you will" becomes "you'll". And so on and so forth. But what happens when you get three words that can be contracted? "You will not" can be "you'll not" or "you won't". A quick google search reveals that "you won't" gets 69x more hits than "you'll not". And what about "it is not"? Should it be "it isn't" or "it's not"? Again, our quick google search shows that "it's not" is about 40x more used than "it isn't". Is there a subtle difference, or is it merely a mark of linguistic trend?

As a possible explanation for the first pair, I'd venture to say that the pronoun "you" is of higher ordinance (whatever that means), than the auxilliary verb "will", and therefore the contraction tends toward the lower-order word, resulting in "You won't". One could then argue that "you'll not" puts stronger emphasis on the negation (although I'm sure the latter construction could be easily a regional dialect thing).

So what about "it's not"? "It's not" is two syllables, whereas "it isn't" is three. Does the copular verb to be have a higher ordinance than the neuter pronoun it?

I really doubt my explanation holds any weight (especially since I only spent about 30 seconds coming up with it), but it certainly does make one wonder. Does one happen in a certain context more than another? It's easy to see if there's precedence, the negating parallel structure is easy to do.

Consider:
A: "It's only a matter of time until the men in white coats come to get you"
B: (1) "It's not only a matter of time, it's a matter of how many men!"
(2) "It isn't only a matter of time, it's a matter of how many men!"

Is it this even a legitimate area of study for linguistics? Maybe, but it's not something I'd want to investigate for 8 months or more.

To close off with a fun fact of the day, let's look at some holes in the OED. For the word comparable they only have listed in the pronunciation "COM-pri-bull" instead of "com-PAIR-a-bull". But I've always pronounced it the 2nd way, and most Canadians I speak to also pronounce it that way. Does the OED only consider British and American standards to be worthy of their attention? How cruel.