It all depends on style. In Gospel piano, most of the notes for soloing are based on the blues scale. In C major that's C, D, Eb, E, F, F#, G, A, Bb. In southern Gospel, more often you use of the major 3rd (E) and major 6 (A) and less use of the minor 7 (Bb) and minor 3 (Eb). On any chord you can employ the added 2, that gives it a country flavor. Added 2 on a minor triad has a nice bite. On a major triad it sounds happy.