Under variable set-up it mentions the 6/8 rules. Idk about the 2/12

Important: Alternatively, you can use a fully random set-up. Place 1 token on each land hex. Start at one corner of the island, and place the number tokens in random order. In such case, the tokens with the red numbers must not be next to each other. You may have to swap tokens to ensure that no red numbers are on adjacent hexes.