You can sacrifice 7x2* and always get two rewards from that tier, so you save one toon compared to 2x4x2*. That said I'd be curious with regards to a comparison between tier I and II sacrifices as well.
Hmmm thanks for the tip, will keep in mind in future sacrifices
Originally Posted by Jofer16
Yeah I focus on efficiency. Also pro tip, 10x 2* is better than 4x since you get 3 drops at the halfway point with 10 instead of 3x 4 at 12. Best is getting 3 rare souls from 10 2* Guessing you hadn't realized the halfways give 3x the rewards.