| Paradozen |
A medium creature (probably) has 8 bulk before gear, and a small creature (probably) has 4. Petrified condition tells us that petrified creatures have twice their normal bulk, and suggests 16 for petrified medium and 8 for small. My own extrapolation infers 2 for tiny creatures, which is important as my first character will definitely have a familiar somehow, and probably carry them around in a backpack.
I'd really like to see this detail explicitly stated in the bulk section of the final game.