Okay, so I got a water fountain and put it on the lvl 100 air knuffel with all its points in shadow, which also had the cat on it, to go dig in water because of the increased FP chance.
This first day, with 50 digs I gathered 640 fp. So I estimate about 10 days for the fountain to pay for itself with a lvl 100 knuffel WITH Amaly the Cat, or about 20 days without the FC item.
We'll see how that estimate/average changes over the next few days...
Also it's true I gathered troth tokens again, time to roll. (That was a very clever way to link these, rebecca, I'm glad you mentioned the memory trick)
Spoiler
Here are your random numbers:
140 235 342
Timestamp: 2016-01-08 01:13:29 UTC