I wrote a little about it back then: @phoenixskye/preview-of-daily-pay-and-earn-percentages-according-to-rank-and-deck-quality

Basically 3 Diamonds + 27 Meteorite is better than 30 Shadow. However, even at that point, you're just only 4% more than a 30 Meteorite deck; the most important thing is staying in Mythic.