The more vertical your instrument, the less you have to bend your left wrist. A nice guide seems to be that the nut should be about one or two inches above your shoulder line.
Freedom of movement is a great goal to work towards.
Open up your hands and place your thumbs closer to the edge of the instrument, and use them as pivots, resting the inside edge of the thumb on the instrument, not the flat pad of the thumb. These are very different from guitar placement, so you may not like them, or want to use them, but they work for me. I used to have a problem with my playing position, too. So if you have an adjustable belthook, you might try adjusting it. Tom, the Stick's nearly vertical position was designed to allow the hands more freedom at a perpendicular angle to the fretboard.