Thankyou everyone for your input. Following ED's little tutorial and tips from others I was able to get the right results. One funny thing though, my view port after performing the shell command displays a polygonal silhouette, though if I export and set angle setting low the geometry is smooth. In the past I would simply lower meshing angle in view options but here it doesn't seem to react at all. (Edit: No wait, its only appearing polygonal when shell is set to flip...bug? Viewport? )
In any case, its not really an issue for me.