A second slot for a Selector Tag ([4] or [9]) could be added to the Unboxinator to choose which one you want, but if you didn’t want to do that I’d recommend 1 to 9, since that’s what vanilla Minecraft and most mods tend to implement:
-
1x <Material> Ingot→9x <Material> Nugget -
1x <Material> Dust→9x Tiny Pile of <Material> Dust