I agree with the above, this is very risky & you can see your bank & profits dissaper in a very short space of time. I also agree it can work ferrari jack, however the risk is massive.
Have you thought of trying to make a profit of maybe just £30 a day with say a £1000 bank stopping at the first winning favourite, maybe just sticking to one meeting rather than covering every meeting ??. You may also want to think about the prices of the favourites you are backing, e.g lumping on a 1/4 favourite that gets turned over is going to hit you hard, & means that you are going to have to risk a lot on the next fav to make a profit.
As a rule, I would say if you had a big enough bank, then yes it could work, but you could find yourself having to put a few very big staked bets on for not a lot of profit if you hit a losing run.
Wasnt there a time a few years ago when there wasnt a winning favourite for 3-4 days ???, this would wipe you out unfortunatley.
I would suggest you test it in here & see how it goes, you may find its not fool proof at all ,
Good Luck
