Solar system scale

Making a solar system to be used in a 3d scene where the user/player will fly through it. Will have many solar systems, a mini galaxy. Standard stuff. What are the opinions on scale? Sun is a 1 and planets in the .001 range and moons smaller than that? Or take the suns up a bit to X? Then what about ship scale?

It’s really up to you, but if you start using extremely small or extremely large scale values you will start to have numerical accuracy problems. See this for more detail and explanation than I could ever give.