What I do for panel line shading is copy them and make a new layer. If you're useing photoshop use "Color Overlay" And make that layer black or dark brown. Then use "Gaussian Blur" and blur it around 1-2. After that make opacity maybe 40-70%.
It looks good for your first skin. Remember what I said weathering makes or breaks a skin. One thing I do see, I dont know if yo were going to do it or not, is the fabric outlines on the control surfaces.
