Hi Mark, no you can't just grab any surface that's part of solid and scale it, you would just need to reconstruct that object with your original sphere scaled down and repeat the same steps you did to build it in the first place.

In the future I do want to make a deeper history function that would allow for the kind of editing that you're asking about but mostly MoI is focused on making things as easy and quick as possible to just do the initial drawing.

There are other CAD programs that are focused on that kind of history, like SolidWorks and Alibre, if you need to have a deep history function you can use one of those other programs to get that kind of functionality rather than MoI - the tradeoff is that they are not as easy to use and don't have the same kind of fast and fluid initial drawing that MoI has.

- Michael