Record 6.7 player counts; 6+ players start on Yellow (D48)

RULES.md: 6+ players start on 3, and any count may start on 3 for a
shorter game. Balancing simulations keep start 0.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

RULES.md

@@ -40,8 +40,10 @@ Each player has a position from **0 to 17**. Your belt is the segment you are in
 
 - 3–4 players: one pawn per corner Safe Room.
 - 5–8 players: two pawns per corner Safe Room. Players sharing a corner are never consecutive in turn order.
-- Everyone starts on track position 0.
-  *Variant to test with 6+ players: start on 3 (Yellow).*
+- Everyone starts on track position 0 (White). With 6 or more players, everyone starts on
+  3 (Yellow) instead.
+- *Shorter game:* with any number of players you may all start on 3 (Yellow). It saves about
+  a fifth of the playing time.
 - Choose the first player at random; play proceeds clockwise.
 
 ## Turn
@@ -174,8 +176,7 @@ All other cards are shown and resolved immediately.
 
 ## Rule variants under test
 
-Parameters to validate by simulation: starting on 3 with 6+ players; square mix; game
-length at 3/4/6/8 players.
+Parameters to validate by simulation: square mix; game length.
 
 Tested and set aside (simulator switches only): Exam ties to the defender; best-of-3 Exam;
 Kiai +1.