Try this
2 units on the shortest price , must be $2.50+ , otherwise ,no bet that race
THEN
1 unit on the others, as long one of them is paying $10+ otherwise no bet that race.
Total O/L 5 units per race

We are trying to use the shortest price as a saver.
Try & stop betting at that venue once a selection that qualifies for value wins & continue with the other venues

I feel one has to cherry pick the races that present the said values , otherwise , one will be pushing it uphill.

Cheers.

__________________
Cheers.