If you want to focus on OTK with vultures when killing all the malignant cells on the opposite field, then you could do it better if you use a skyblitz. That way its enough to have 3 vultures on the board when killing 23 cells/skeletons. You should still have at least 4 vultures in the deck though, so that you can have them in hand earlier. The arsenics are not useful for that goal, so you can drop them. OTOH, you need to have a skull shield early, so better have at least 3 in the deck.
So -2 vultures, -2 arsenics, +1 skull-shield, +1 skyblitz (or 2 to avoid bad draws where it is at the bottom of the deck).
You can probably drop some pillars too to get to a 30 card deck.