I'm 64 kg, and I use a 90 liter freestyle board with maximum sail size 5.2. Larger boards feel heavy and sluggish to me.
At your weight (68kg), a 110 liter board seems like a lot. Think of it this way: If a lightweight like you or me is on a 110 liter board, almost the largest production size, what does that leave for a 85 kg bruiser? Speed-sailing perhaps?