You'd have to set a different rule for each stake amount and use 'if price less than'
e.g. rule 1 - if price is less than $1.10 then lay $100 a minute before the race
rule 2 - if price is less than $1.20 then lay $50 ...

need to work on the stakes though, as multiple rules will run if its less than the first rule.

New features constantly being added which includes the option of setting a price range, which will allow you to set a different stake for different price ranges.