World Champ scoring system

Hi guys - here we go again - I need to sort something out with this so can
each team captain sort out a system that they think is agreeable to all?
Something including surrenders on turns 1-10 (negative points), 11-20
(slight positive), 21-30 (no change), 31-40 (negative) to the losing side.

Suggestions are something like

3 pts for a win
1 for a draw (ie game ends on turn 52 with no winner)
-2 for an early concession (t1-10)
+1 for t11-20
-1 for t31-40

Clint