So now I have a skeleton with 8 slots to work with. Of these 8, I can safely assume four of them are either going to be Duress, Extirpate, or Chalice. Need some input on this.
Why not run both Chalice and Duress? Actually on second thought, you only run one fetchable black source and from my experience it sucks fetching an underground sea and having it wasted next turn. But since Oath's mana curve is so low its still possible. In my Oath builds I always run a lone copy of Life from the Loam. You can reccur stripmine which is a powerful play with chalice @ 0.
Therefore I would go:
4 Chalice
3 Duress
1 Loam
Just a suggestion, but I'm no expert at Oath
I think the red is only good for SB cards, or god forbid, hardcasting Razia.
Since most Oath decks run Crop Rotation to find Orchard, why then does no one run the lone Enlightened Tutor for the 5th Oath? Is that one W mana that prohibited? So far this decklist has 8 potential W sources, 9 with Crop.