The color of the flight suit is one of the most persnickety things because lighting just plays tricks all over the place.
You might try weathering the lighter suit first using something washable like Dirty Down. I don’t think you want to take the darker suit any darker, so leave that one as is. What you need to do is figure out if the lighter suit needs only weathering or a bit more dye and weathering. Good luck!
I don’t think you can make a bad choice here in the end. It’s good to look at the suit under different lighting conditions and with the vest and armor on if possible. Just go with whatever makes you happiest in the end.