Ahhh! That works!! I had overlooked the Clipping options, as I thought those were global limits that applied to all curves [for setting limits like NTSC StudioRGB color]. I’m glad to see that the clipping values can be changed without affecting existing points.
NOTE: Your Group>Append idea is actually the basis of my current project. I’m building a library of custom nodegroups for common operations (keying, luminance conversion, etc.) based on the flowgraphs in Steve Wright’s book. If I save all of the groups into one empty project file, then I will have a library of compositing tools from which to import for any Blender compositing task.
Given the power of Blender’s basic nodes, you can build just about anything you need for compositing. The ability to group and then append means you only have to build the tool once – great functionality and so flexible.