I would like to know the percentage of points a team is expected to return based on the spread
Example
-1 expected to get X% of the total points scored
-1.5 would mean that a team is expected to make/be responsible for X% of the total points scored
I am fine with the formula (would prefer) or a simple scale
I would prefer the formula as then I could do it myself
Not sure if this is what you're looking for or even the correct way of thinking about it, but couldn't you just divide the total for the game by 2, Subtract the spread, then divide by the total again?