Dear Sara,

When commercial companies draft pants, they use the hip to begin the
draft. Use a larger size, and take in the waist. In any case, when you
use a new pattern, you need to make a muslin first before using your
good fabric. You may need to alter the crotch length or depth. Make
all the alterations by basting the muslin together, and then fit it and
use the muslin for your final pattern.

Teri