Been working on Barry's cool method suggestion with trim and blend and while not as good as Barry's am starting to get it a bit. The problem is material missing from the front profile of the neck - in my original drawing you can see the blue lines are the front of the headstock and the red the back - when using trim and blend we use the back profile which of course doesn't include all of the neck profile - just the back of the transition. I tried using the method with the front neck shape with no luck - not sure what I'm doing wrong. The file is attached. Thanks for any and all suggestions - in the mean time will try to combine the two shapes and see what happens.