Kurashiki or Okayama for ferry to Naoshima?

I would like to make a reasonably early start in visiting Naoshima, and I was wondering if makes more sense to stay overnight in Okayama for that rather than in Kurashiki (which would be my preference).

I see it's about 2h from Kurashiki to Uno port to catch the ferry. On the other hand, Okayama to Uno deosn't seem that fast either (1h?), so perhaps starting from Kurashiki doesn't add that much?

Grateful for any advice.

The train to Uno departs from Okayama. Kurashiki is a 20 minute train ride from Okamaya (5 departures per hour; first departure at 5:34). That's the difference.

Because of the ferry timetable, consider staying in Takamatsu - it is a different option.