Starting to look good

A few Q's and comments. This is what I'd do not neccesarily what you
should do.
What method are you using to blend you layers? It's hard to explain and it's personal preference so if you like em leave em, but your panel lines look a bit yellow. With 1024x1024 skins I use a 2 pixel wide anti-aliased black line on a normal blended layer with 15-25% opacity. (like this)

What size/res is the skin your working on? (all sizes I give are for working on 1024x1024 so you'll have to scale down for 256x256, should have mentioned that before)
Carefull on adding random weathering, I like the lightness you've got on the mid panel highlights. BUT careful on how you place them, I usually orient them with airflow and don't overlap them. ask yourself what is causing the damage to the paint and place them accordingly.
I also neglected to mention in my previous post, I turn the hardness way down when doing this stuff. These are my brush settings.

Weathered wing looks much better than the unweathered one. Keep going

Gatso