For you number crunchers - I began the farming at the 4:00 mark. In the 3:15 from there to the end, I gathered 106 Rigogen.
Instead of performing a full S, I stopped when I reached the midpoint on the return flight, so about 3/4 of the bay was harvested.
Extrapolating, I could have gotten about 135 Rigogen from the bay, in about 4 minutes, with let's say 4 shards.
But this is not 135 * 15 times per hour. Because the bay would be exhausted.

To harvest more, you need to fly to a new harbor and begin the process again, including re-crafting shards.

You can gather it pretty quickly, but I tend to prefer harvesting it one harbor at a time, expecting that yield to be between 100 and 200 Rigogen.