To get a gauge of how those that participate perform, why not do a Dutch Book excercise of each of the five selections to return a $100 i.e.

A: Rated $4 outlay = $25
B: Rated $6 outlay = $ 16.50
C: Rated $8 outlay = $12.50
D: Rated $10 outlay = $10
E: Rated $12 outlay = $8.50
Total outlay = $72.50

If A won at SP odds of $5 then the return would be $125, a profit overall of $52.50.

If on the other hand A won at SP odds of $3 the return would be $75, a profit of $2.50.