Let's face it. Players can't pay hundreds of thousands of Crowns to encourage the masses to add "purple" to a specific bin, more than any other color.
I want to recommend PARTIAL boosting.
Allow a player to contribute to a Crystal's pay rate, from 1 to hundreds of thousands of Crowns. Each crystal for each strata, would have a (not shown) number of units at the current price, which would increase as the players raised the crown amount - trying to encourage zone changes. As people contributed, that amount/price would fall as the boost ran out or rise as the boost filled up.