I think Ruby's more of a Tzeentch follower. Remember that even after everything, she never lost hope and the desire to bring change.

Jaune is a better Khornate in comparison, Let's see. He wants to get stronger and to get more skilled at fighting, he wants to protect his remaining friends, is pretty wrathful and vengeful, believes in honor and justice, pretty good at tactics and strategies in regards to aspects of warfare, His first act in his fight against Cinder is to allow himself to be overcome with rage and later throws himself in front of Nora in order to shield her, Don't forget that out of everybody, he's easily the angriest out of all them. Not even Yang can match his rage. Which makes him a better Chosen of Khorne. afterall, Khorne not only embodies negative aspects but also positive ones like Justice, Honor, Determination, Courage and Discipline. Aspects that are easily found in Jaune than in Ruby.

In regards to their Justice belief, Ruby is more optimistic and believes that Justice should be fair to both parties with due process, Jaune is pessimistic and his belief of Justice is more of "Pay Evil unto Evil" and "An Eye for an Eye". A belief Khorne would be absolutely delighted to see if Jaune falls to his clutches.