I know what you mean Blocka, and of course you are right [as was Mark], but the idea is not to work at or arrive at a market price for the field or to create a book, but just to see the relationship of your selection[s] actual value as a bet.

If a selections SR is 30% we divide that into a 100 and we get $3.33. That figure represents it's overall true value. Common sense then works out a suitable price that would reflect overlay value. It could never be purely mechanical of course.