Ok, was I the only one that thought to themselves:
1. I'm sure work is dry when it doesn't explode in the kiln when I fire it.
2. I'm sure work is dry when a piece comes off in my hand when I pick it up.
3. I'm sure a piece is dry when it shatters to bits when I drop it off a ware board.
It might be interesting for you to make a few blobs of clay the approximate size of your miniatures and break them open at different time intervals so you can get a "feel" for what not nearly dry, almost dry, and dry as a bone looks like and feels like. I have learned much more by the pieces I have bashed than any I have fired and sold. Congrats on finding clay, enjoy the journey!