The article is a bit vague about the castling and promotion rules. The choices you made in the FSF settings (O3 castling and no promotion to Prince) seem the logical ones, though.
Anyway, I put in some section headings, and added an Interactive Diagram in the Setup section, playing by these rules.
And you are right: this 'promotion to King' business seems a bit nonsensical: you simply win by reaching the last rank with a Prince, so there is no need to change it for another piece. There is a question, though, whether it is allowed to promote it on a square attacked by the opponent. In the Diagram I programmed it as an immediate win, because the rules explicitly say that you can expose a Prince to capture. But if you would really promote it, it would no longer be a Prince, and you would have exposed the resulting King to capture. So this 'promotion to King' could be just be a roundabout way of saying that this is a delayed winning condition, where you have to survive the opponent's 'after-move' in order to win (like in King of the Hill). But this interpretation is subverted by the mention of the first variant, which uses the resulting King as extinction royalty, so that it could be exposed to capture.
The article is a bit vague about the castling and promotion rules. The choices you made in the FSF settings (O3 castling and no promotion to Prince) seem the logical ones, though.
Anyway, I put in some section headings, and added an Interactive Diagram in the Setup section, playing by these rules.
And you are right: this 'promotion to King' business seems a bit nonsensical: you simply win by reaching the last rank with a Prince, so there is no need to change it for another piece. There is a question, though, whether it is allowed to promote it on a square attacked by the opponent. In the Diagram I programmed it as an immediate win, because the rules explicitly say that you can expose a Prince to capture. But if you would really promote it, it would no longer be a Prince, and you would have exposed the resulting King to capture. So this 'promotion to King' could be just be a roundabout way of saying that this is a delayed winning condition, where you have to survive the opponent's 'after-move' in order to win (like in King of the Hill). But this interpretation is subverted by the mention of the first variant, which uses the resulting King as extinction royalty, so that it could be exposed to capture.