It's not as good as the practice pad, as you can't take back moves, and you can't quite do Brainking's rules exactly (the king can always re-enter the central square in my implementation).
The settings required for an approximation of our familiar tablut are:
Layout: Jarlshof I; King strength: weaponless; King's objective: Board edge; First move: King and Defenders; everything else is as set by default.
While it has shortcomings as a practice pad, it does allow you to experiment with other sizes of board and rules. There is also inadequate documentation.