Thanks for everyone's advice on sizing! I've decided to go with the smallest size and hope for the best in blocking and making up an extra 1/2 inch or two in the button band if necessary.
My buddy Oscar helped me get a big chunk of Forecast
As you can see, I'm going with bobbles, and bobbles all around, rather than plain cables. (Can I tell you it's all I can do not to mistype "boobles"?). So far I'm pleased as punch with it. They make for a sweater with a lot of character and a definite vintage flare. They're a bit difficult to photograph. In fact this whole sweater is difficult to photograph - between the stitch patterns, the color, and the shape (esp. since the needles I'm using are shorter than recommended... gotta change that). If you click on the detail shot below you can see them a little better:x-posted here