There's a fair amount of evidence that award tickets will continue to earn MQD ("no change in redemptions" suggests that, for one thing). So if 100 miles redeemed continues to be 1 MQD, that makes the Reserve rate 1.1 MQD per $10 spent (no bonus). For 2x spend on the Plat, that's about 0.7 MQD per $10 spent. The miles also effectively let one bank MQD.

For existing Diamonds earning 11 RDM per MQD flown that implies 1.11 MQD per dollar. Using the Reserve (3x on DL spend) to buy tickets is another .13 MQD per dollar, or 1.25 or so (considering that taxes count for the Reserve), so if earning and burning, DM is 28k or thereabouts, without needing to put non-DL spend on the card.