Oil Washes on Historical Miniatures?

[Captain Harlock]

I would recommend to get some artist's grade oils from any good brand (W&N, Talens, D&R, Schminke etc). The sets made by scale model companies can be enticing but have in mind that at best they are just repackaged artist's (or student's) oils, and they usually dont offer real primary colors but convenience mixes that you dont really need. Artist's series generally have alot more pigmentation and in this case you really need that in order to produce nice washes and color filters.
The best budget solution imo are the Talens series van gogh as they sit somewhere between the artist's and student's grade. The next one is Winton series by W&N but sometimes they dry up abit grainy. Ask me how I know 

You can use W&N sansodor, or any good brand of odourless thinner. White spirit from the hardware store usually is too agressive for the acrylics underneath but it really depends from the brand. Sometimes there are cheap brands that work just fine.