Hi again, mate. As every one has said, the choice belongs to you. Did your OB give physiological reasons why VB would leave you with the pain whereas C/S will not? (That's just out of interest for me! Sounds like it isn't all that relevant given your current feeling of wanting the c/s, which I do understand and of course respect.)
I'm certainly no expert, but I believe that it shouldn't pose too much of a problem if you were to go into labour before your c/s. Just transfer to hospital early and they can prep you and do it then! It is unlikely that your labour will be fast and furious (though granted, for some people it certainly is), but perhaps as soon as you feel a different type of contraction then call your hospital or OB.
Probably I'd think the best thing to do is try not to stress. You sound like you are working everything out and feeling at peace about the c/s - hang on to that! And all the very best for a wonderful birth and a lovely, pain-free recovery and babymoon.