Ready to Start Soft Waves afghan

I have gathered my yarn, Red Heart Soft - 11 different colors, maybe a few more. I've agonized on what order to place the colors
and have finally decided on a sequence (really just tired of obsessing on it).

I'm making this for my son's girl friend for her birthday. We were chatting on AIM a few days ago and she asked me if I could repair her baby blankie. She sent a picture and it was full of holes... I mean really full. It was the epitome of the well loved and well used blankie. She jokingly said maybe she should just frame it. I thought that was a good idea.

I had already been thinking of making her an afghan before this conversation, but afterwards it seemed like the perfect gift for her. She will be 21 in November and an adult blankie to curl up with when the big bad adult world kicks her around might be a welcome thing,

So I've decided on Soft Waves. I'd like it to be a generous size but I'm not sure how many repeats to use . The pattern repeat is 12 plus 3.

Soft Waves has been a popular pattern here. How many repeats have the rest of you used for an adult sized afghan?