Metalizer Variation & Weathering...

Hey Gang,

Getting ready to paint a 1/48 Hasegawa P-38J.  Gonna use Model Master Buffing Metalizer- Aluminum Plate. 

1. How do I vary the shading and shininess to replicate aging panels?   

2. What's the best way to weather it?

3. What about washes? I generally use artist oils in turpentine.  I'm assuming that would be a problem even with the metalizer sealer.

4. Lastly, is there a better alternative to the Metalizer?  What about these powders I've seen on the web-shops?  I had a brand called SNJ that was a combo of metalized paint w/ powder that worked great but after 15 years in the attic it's no good and I can't find it anywhere. 

Thanks.