Single stage Omni paint: How long before I can sand?

Just had the interior painted. Not real happy. Used single stage Omni and need to re-paint a few areas.

In order to apply filler, can I sand the new paint and apply filler or do I need to get down to metal?

How long should the paint cure before I can do this?

This is the interior of my 67 Dart.

Thanks, Kevin

Cure time on Omni is 24 hours at 70F. Depends how much filler you need if you need to get to metal. If you can fill with a glazing putty then 80 grit is sufficient for adhesion. Otherwise plan on 24 grit to rough up the metal.