I also generally use Vallejo paint, for the price, but also because i can find them more easily nearby. Foundry paint is very good with there 3 color method (use them one for the bavarian brigade), but i found them expensive (shipping costs).
For my Iste & 2nd Fre brigade (light and line) i used the vallejo 70962 Flat blue. My inf guard are receiving Citadel foundry Mordian blue (simply because i have 3 pots and they must be used so the Fr Guard are getting they). At the beginning i didn't use the 3 color methode, but it seams i am using 2 tones now (Austrian Line).
If you find extra info vallejo napoleonic versus russians, please post the info. Don't know what vallejo colors i need using on the rus infantry.
Greatings