Based on feedback from the Machina Arcana insert, I evolved the design. Specifically, the walls of the card separators are now angled so that the wells work better for un-sleeved and sleeved cards.
In the initial design, the ridges separating the card decks are vertical. In some cases, un-sleeved cards can slide between wells and get damaged,
By angling the separator ridges, un-sleeved cards can not slide between wells.