I started learning Edvard Grieg's Piano Concerto in A Minor Op 16, and I came across a part of the music that requires my right hand to do the chromatic scale twice at the same time, separated by thirds. That is, one hand is responsible for doing two notes simultaneously separated by thirds and traversing the chromatic scale.
Is there a standard or preferred fingering for this? It would be for the right hand, going down the scale, if it matters.