By "grid" do you mean the large radial coordinate reference, or the small diamond texture? The large radial system is useful either way you have it. The small texture does not seem useful to me - it just makes the whole star background less clear. Can you try it without that texture at all?

As far as light background or dark -- the dark background/ light stars seems prettier, but the light background / dark stars may make it easier to discern details.

Did you generate the galaxy yourself, or is it a real telescope image?