This mechanic means, "When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less
Fountainport feels a lot like Trading Post, an artifact that sees a lot of Commander play in its own right
Still, the ceiling here is a massive vanilla creature, and that's not completely gamebreaking
A general piece of advice is to aim for a smooth distribution of cards from each ink cost, ensuring you can consistently use all of your ink to affect the board in the early turns
It doesnt get any more one-sided than Ruinous Ultimatum, unless, of course, you play Cyclonic Rift
Would I recommend three decks as the number for your whole collection