Here is the spray paint color list that I used on my wife's Boushh:
http://www.thedentedhelmet.com/f68/boushh-wip-now-complete-501st-bh-82371-a-47893/
All paints were Rustoleum.
-Helmet-
The base silver color: Silver Metallic #7271830, after spraying this if you are doing a layer method use a matte clear coat on it to help with paint adhesion.
The main color I used for the helmet: Flat Brown #214085
Used for weathering:
Ultra Cover 2X Satin Expresso #249081
Satin Enamel Dark Brown #241239
Satin Enamel Chestnut Brown #7774830
Enamel Leather Brown #7775830
Gloss Dark Grey #249115
-Armor-
Main Color:
Enamel Leather Brown #7775830
Weathering:
Flat Brown #214085
Ultra Cover 2X Satin Expresso #249081
Satin Enamel Dark Brown #241239
Some flat black was used for the weathering on the helmet & armor as well.
The weathering was done misting the colors over the helmet & armor lightly to give it an irregular & worn look. Experiment to get the desired affect.
The majority of the damage on the helmet was done with layered method, but some of it was done topically.
I hope this helps if you have any other question let me know.