i have requested trigger yesterday for greyhound lay , i need modification on it , problem i did not explain it correctly , 
Selection Rules : 
Market : greyhound win market 
Rules : lay bet on favorite is price is below 2.41 at 30 seconds before race start 
Staking Rules :
Double the lay amount after a win, reset to default lay amount after 2 wins in a row or after loss, 
example :
Starting layamount : 4
1-> Lay $4 ->Win
2-> Lay $8 -> Win 
3-> Lay $4 -> Win
4-> Lay $8 -> loss
5-> Lay $4 -> Win
6-> Lay $8 -> Win
7-> Lay $4 -> loss
8-> Lay $4 -> loss
9-> Lay $4 -> Win
...................
Hope now i clearly explained