With the 100% xp bonus you get 160k in 3-4 minutes, depending on how fast behemoth decides to spawn. As seen in the video, you need to be behind the invisible barrier to use the B/O attack. Wearing these Casual Outfit (no jacket) let's you get a decent amount of crits to kill it faster.
With expericast you get like 20k like every 30 seconds, but who has enough coins to get to level 120?