Easy way to get legend coins?

Stereo, do mind doing the calculations about how many level 70 bow and crossbow arrows it takes to level each time, counting in the % to make double mastery which increases each level?
That would dumb it down to punching in numbers 18 times and AFKing.

I don't know offhand what the mastery formula is, that is, what exp you gain 1 level higher, 2 higher etc. from the recipe itself. It's about a 10% difference in speed though, and the plates cost 5x as much. (then again, you use a Super Moo every 6 plates, so you're spending 100k on the Super Moo and 12k/36k on the plates... so it's only about a 10% increase in cost)

Tried to get a look at it by checking out the mastery reward of other items, and the game crashed -_-