Nice skins Kempf! Keep it up... it's addicting.
I've included a link to .pdf files of a few of my skins including the alpha files. Not that I'm the best skinner around, but it may prove interesting. I think we all have different methods of weathering, etc. The alpha is a good way to get that bare metal under paint chips look.
BTW - if others would be willing to post their pdf (or Gimp) files, I think it would be interesting to compare methods.
Link:
https://www.dropbox.com/sh/5mv1gemia4uf7hd/AABblnMBnRTl49WfjWSGO_lPa?dl=0