weighting team totals....fezz and math guys

weighting team totals....fezz and math guys an example tonight using 15/54.5 for game..... a and m shouldbe 34.75, smu 19.75. i played under 36.5 team total for a and m. how big a play should this be?
I don't have the numbers on this, but worth a bet yes
a good bet, but a loser. got 1 .75 points crossing 35 with steam on the dog and the under, it still lost. played for about .75 units.