I've come across some interpretations / translations which come down to the following ruleset (adjusting Clark94's list below):
1) White wins when the king reaches an edge square. 2) The throne is hostile. The throne isn't hostile to white when the king is on the throne. Once the king leaves a white piece can be captured against the throne. 3) The king can capture. The king is captured in the same as his men. 4) A king on the throne must be surrounded on all four sides and a king adjacent to the throne must be surrounded by three sides, much like here on this site.
Many years ago when we were investigating and discussing the rules, I quickly dismissed the variant where the king can capture as being way too easy for black even when the king is armed. Any experiences to the contrary?
(kaŝi) Se vi volas ludi kontraŭ ludanto de simila nivelo, vi povas difini intervalon de BKR ĉe invito al nova ludo. Tiukaze neniu kun BKR ekster tiu intervalo povos vidi/akcepti ĝin, (Katechka) (Montri ĉiujn konsilojn)