Brute force works here.

OK, i. has only two choices, and they are pretty similar. One die has a better chance of rolling 12 [guranteed win!] but this is counterbalanced by also having a better chance of rolling 1-5 which would lower the chance of winning.

Can you quickly tell which is better? And how difference it really makes?

Game #13501  •  ElihuRoot (Giant) vs. irilyth (Buck Godot)  •  Round #4

random random

Opponent's turn to attack

(20) (20) (20) (20) (20) (20) Button: Giant Player: ElihuRoot

W/L/T: 2/1/0 (3)  •  Score: 84 (+8 sides) Dice captured: (W=12,W=12), (20), (10) (20) 5 (20) 11 (20) 7 6 (6,6) 6 (12)  1  (10) Dice captured: (20), (20), (20) W/L/T: 1/2/0 (3)  •  Score: 72 (-8 sides)

Player: irilyth Button: Buck Godot (6,6) (10) (12) (20) (W,W)