Here's the OR file for my
silver-modded Magnum Payloader.
I use this as my source "silver texture", which works pretty well at 100 dpi (which is what I and I think you do all your OR decal work at):
View attachment 288646
General method:
1) Adjust brightness/contrast of the silver as desired for the rocket
2) For solid colored parts, create a new image in the appropriate size.
3) Copy/paste the silver texture into it. If you need it to be larger, then do more copy and pasting, don't ever resize the silver texture.
4) How I converted the Magnum body wrap decal, using Paint.net (what you should be using if at all possible):
a) Open decal file
b) Create new layer and copy silver to it
c) Go back to original layer. Using magic want, shift-click each area to be converted to silver, until all are selected.
d) Invert selection (ctrl-I)
e) Go back to silver layer, hit delete
Everything should look good now. Either merge the layers and save, or first save as PDN file with layers intact, for easier modification later.
Any questions let me know. I used this general approach on the Diamond Cutter OR file, and it definitely gave me a good hint what the silver would look like. If you want to do gold, you'll have to go find a good gold texture sample to use as a base (or you could convert the silver, but that's beyond my pay grade to do effectively.)