I was thinking more in terms of modifying the shape to add more kidney and back of neck protection. Also, I have a long torso and arms and large neck in relation to torso width (a fat-necked, skinny chimpanzee).
Some better-framed questions would be:
1. Does the pattern include all of the sizes, or just the size you order?
2. How closely do the material requirements match the material provided -- is there any excess to play with?