I would love to know the same thing. I've been scouring the forums to find an answer, but no luck yet. If I find anything, I'll let you know.
For others who follow on this thread...
The colors and fonts are handled by my custom theme, but it is the chart-formatting details that I am concerned with. For instance, is there a way to have a pie chart default to a flat (no 3D shading) pie chart with white outlines and value labels? As it is now, the default pie chart that comes up has 3D shading (which only serves to wash out the custom color palette that I have selected, to the point of unrecognizability), and has no outlines, and no value labels.
I am building a Template for widespread use and my client would like charts to default to my custom style. Can this be done? Or would an end-user of my template need to manually format every single chart they create to match my custom chart?
If someone knows, definitively, that this default formatting cannot be done, please let us know. I'd love to stop searching for the answer if it does not exist.
Thanks