A Time Apart: Fred Corrective Blendshapes Upper Body

I have found it quite difficult getting to grips with the corrective blendshapes as I got a lot of distortion and popping, I found some solutions - mainly I needed to be more subtle with my adjustments. On the elbow I tried to make it more of a point by pulling the middle edge outward causing it to pop when the arm was in the neutral position - the solution to this I found was to move the edges around the centre inward instead of bringing the centre edge outward. When editing the shoulder twist I get distortion and I think it looks good without a corrective blendshape or at least it doesn't need much done to it so I have left both sides without a blendshape (the fifth image shows the distortion on the right shoulder I got regardless of how I edited the shoulder twist). The pose editor wouldn't mirror for the shoulder joint because they are asymmetrical so I had to redo the blendshapes for the right side - the elbow mirrored successfully, for now the below screenshots are the best I have so far.