Quote - 28 hours in, still got some grainyness and red 'speckling' in the darkest parts of the shadows, though most of it has smoothed out, about 500 samples/pixel.  I am just guessing here, but at the rate it is clearing up, I would think I would need about twice that many for a final render.

Most images don't look very good until the sample rate rises above 700 per pixel - some need even more, especially those with heavily shaded areas. Brightly lit images need a little less ;).

Laurie