Thank you very much man, I appreciate the feedback.
For the flight suit, I used a little soot black, and mostly regular black around the ankles. I followed this up with khaki and mid-brown (unfortunately nicotine is not available in my area so I used khaki instead but nicotine is more accurate).
Then a little mid brown on the thigh pouches, and khaki for the upper legs as well as the arms. Just a little though, the flightsuit is not as weathered as you go up from the thigh pouches.
A little goes a long way but if you overdo it you can always go rinse your flight suit in the bathtub to get rid of excess.
Do it in small bits and then let the suit dry, look at it in both outdoor and indoor lighting.
For me, I only used dirty down as a base. I added more intricate weathering with watered down acrylic paint and then finally powders. Powders are great, and look the most natural in my opinion - but they do not last forever (need to be reapplied).