Thanks to Anne of Glamour-4-you, I can now make a PCP scarf, no worries !

But ...

I want to make a shawl.

I left the question in the comments on her site, but she responds to these only very occasionally; and it could be weeks before I hear from her.

Can anyone here tell me, please ?: when casting on, do I do as many complete iterations of the colour range as gets me to roughly the width I want, and go from there ?