Hello my little Chaos Brother. To paint Chosen I'd do something like this.
kantor Blue, Macragge Blue, altdorf guard blue
1. Kantor Blue Base
2. Wash Nil or nul oil w/e it is
3. clean up with kantor blue again
4. macragge Blue highlights
5. Altdorf guard blue
Id do this for a quick but nice looking job. I don't use any
gw paints so I cannot help you to much but I helped you some. Let me know how it goes! looking forward to see theM!