UPDATE:I found that when keeping the wrists (especially the right hand) level, parallel to the keybed, most of the tension in the forearm is reduced. Also, sitting further away from the keybed also helps in this piece, because that way your forearm can swing from left to right easier, without being restricted by the upper arm and shoulder. The optimal position for me to sit in, is when my elbows can come together easily, without having to bring my arms in front of my chest.Hope that helps some of you who may be studying this piece!