Item drops

[Taugeshtu]

so do we want to create multiple pickups, one for each item, or one pickup for all items of the same type?

Unless we're breaking chest/furnace - multiple pickups. Is it possible?
Because it seems to be the best solution - no confusion, still minimal perfomance impact in critical case (I double we'll see a lot of multiple simultanious lapis/redstone blocks dig - so this case isn't "critical" IMO)