Hi there,
If you are able to do a color replace (like a hue shift) on the existing pilot texture, then most of his cloth effects and lines should be retained.
I'd say you might start by working on a copy of the field gray, try using a 'colorize' process to add a subtle tan in the hue you need. Then adjust the contrast or brightness from there.
You could try some texturing brushes or filters on the area afterwards, and see if you like the effect.