Your suit looks amazing! I'd like to know more about how you have done it...
Weathering:
I used black shoe polish (paste not liquid) -
Amazon.com: Kiwi Black Shoe Polish, 1-1/8 oz.: Shoes
I have a kit I've had since high school which has an applicator and buffing brush. I would load up the applicator brush, transfer to the buffing brush and basically scrub it onto the suit and accessories where desired, emphasizing the abs, seams, etc. To smooth out any heavy spots and really get into the crevices I used a damp microfiber cloth. Really made a difference on the white strips on the abs as the texture tended to grab clumps and gave it an appearance of too many highs/lows. I will say after having done it it's not completely permanent and have experienced some light transfer, mostly from the seat of my pants, so just keep that in mind.
Scales:
Angelus Leather paint, silver -
Amazon.com: Angelus Leather Paint 4 Oz Silver
Angelus paints are overall pretty solid but the silver has a tendency to be really thin and doesn't cover nearly was well as any other color I've used.
When i ordered my suit I asked WSL for some extra scaled fabric to potentially redo the shoulder bells but the OEMs were better than I expected. They did include this fabric for free, which was nice, and I was able to use it as a testing area for adding the silver. After some trial and error I got a good feel for dry brushing the silver on each individual scale with a dabbing motion. I know that's not great for brushes but I just have some cheap ones I got on amazon so I wasn't too worried. I would load up the brush with a mild amount of paint, dab the paint on a row until the brush was mostly depleted and then gently brush back and forth of the whole row. I was really pleased with the end result giving it a nice even sheen that provides a good depth effect without going for molded urethane sheets, which I know are becoming available for getting closer to screen accuracy.
Hope that helps, let me know if you have any other questions or would like to see specific detail photos.