I agree this is a winning system, the reason more people don't follow it is because it can be a long time between drinks.

You could add more horses so you are able to bet more often but people look at it this way.

You have $500 on a sat and got a winner so you are still down $400 people will consider this as a losing day but you have to think of it in terms of buying stocks, when you start a series of bets on one selection you have not won or lost until that series is finished so you could have funds tied up for several months until the runner wins.

if you are going to follow this method you need to set up individual banks for each runner, work out what you may need to cover the series of bets and allocate this amount from your betting banks.