The 1 meter radius I’m pretty sure is hard coded in the blender program. Now if you just want to change the display of the measurements within blender you can change the unit scale to 0.0025 in the units panel under the scene tab of the properties editor. Note: For physics simulation and exporting it will still be the larger size. Also when you add a new mesh the adjust last operator(Bottom left of viewport or press F9) allows you to change the radius. Note:Radius is 1/2 of the length. So a 1m radius cube becomes 2m(200cm).
