It helps that Pluto is no longer a planet but not much.
Uranus is 4.5 billion km from Sun and if, for the sake of simplicity, the model is 4.5m wide, that would mean that Earth with its diameter of ~13000km would be a speck just 0.013mm wide. That should be 1/10th of a single dot at a resolution of 200dpi if you are planning to print a map (one dot at 2000dpi but good luck printing that;). You might want to consider adding an arrow and a label.
Uranus is 4.5 billion km from Sun and if, for the sake of simplicity, the model is 4.5m wide, that would mean that Earth with its diameter of ~13000km would be a speck just 0.013mm wide. That should be 1/10th of a single dot at a resolution of 200dpi if you are planning to print a map (one dot at 2000dpi but good luck printing that;). You might want to consider adding an arrow and a label.