A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
I've never understood why MSFT don't see that companies really need to be able to set default CUSTOM tables. (I already voted)
As JohnK says (and the site is great) you can add XML to your template to do this but... (might be a big BUT)
The XML is complex.
openXML is VERY unforgiving, tiny mistakes can break it.
There are restrictions to what is possible in the custom table (though yours would probably work)
It is much easier to use a proper XML editor like XMLSpy or Visual Studio with the openXML AddIn than unzip and notepad. Unless you can find 'VS2013 Community' these proper editors are both very expensive.
Lastly the XML only works if you open the resulting potx file NOT if you apply it to an existing presentation.
I'm not looking for business and I don't think JohnK is either but just be aware that it is not that easy unless you already are aware of how openXML works.