so i have finally made a decision. thanks to everyone for you help and suggestions (including thanks to the mum of the baby the blanket is for).
and the winner is:
i went out and got some more wool on the weekend, so i will have plenty to be able to join it all her way.
my only concern is that last time i joined things carina's way, i had some significant issues with the corners matching up:
still, practice makes perfect, right?