After posting this, I decided to try and see if I could figure it out for myself. (I'm impatient like that.) I started with the pattern that CrochetDad had posted, the one that starts with two wheels, and tweaked it a bit (for example, I do much better with double stitches than triple). I even busted out an Excel spreadsheet and I THINK I have worked out how to calculate the number of chain stitches to start with for any number of wheels in the foundation row. Once I got the foundation row worked out, CrochetDad, I used your instructions for the clusters & shells, but kept with double stitches.
Anyway, here's a picture of the strip I did just to experiment, and a close-up. I'm still practicing, so it's a little bumpy in spots, but I think I have worked it out.
Comments/criticisms/questions are welcome!