Paint Dash with windshield in?

I would remove it for more reasons than just the quality of visual finish. There isn't any paint on the underside of that dash. Might be a whole lot of rust too. Painting the majority of that white makes everything under there much easier to see. I wrap white tape around most of the harness connectors too.
Then there are a half dozen service procedures to do that will be a heck of a lot easier to do with the dash out. Do it right and you may not need to see anything behind there for a very long time.