If wide, I'd go w/band on grain. On the bias w/large band would hang funny.

I'd also match the curved edge of the godets as well as continuing out the wedge shape when determining final circumference of the band. Trying to make the band too small in circumference may make the godets hang funny when the skirt is finished.

Would a visual band trick work of sewing the solid band to the bottom of the godets, lengthening the solid color straight pieces, and then assembling the skirt as originally patterned?