So i assume that water is highest priority for you, and food is of lowest? That would mean if you got 2 highs (water) and 2 mediums (firewood) you would get a value of 1.47. If i tatke 1 high ( water) 1 medium (fire) and 3 lows (food) i would get a value of 1.47 as well. It would be fairly equal.