Obviously?

Not obvious at all to me.

You're catching a flight where your next option is 24 hours later. And what if that flight is full? You being late isn't going to make you a big priority for the airline. And you have the pick of several great lounges in a nice airport.

Conclusion: obviously you want to be there as early as possible. They won't let you check in earlier than 3.5 hours before the flight, so I'd aim for that.