Double racecard numbers is the collected numbers of the winning horses multiplied by two. So if you fancy low-weighted horses to do well on heavy going, selling heavyweights or buying racecard numbers may be a way of supporting them. The market for starting price favourites or favourites as shown in the Racing Post gives punters a chance to back or oppose the most popular horses of the day. In most cases a horse that wins is awarded 25 points, a horse which is second gets 10 and a horse third gets 5, with the quote based on what the market- makers expect the final total to be at the end of the day.
The starting price favourite is particularly hard to judge, not least because a late move in the market can mean a change of favourite and suddenly you are supporting a different horse to the one you were expecting to be backing. If two horses go off at the same price, the lowest card number counts as the favourite for the bet. If you rate a particular jockey—or think he is useless—the jockey markets allow you to back or oppose him on his mounts that day.
If you think AP McCoy will be on fire on a Wednesday afternoon at Kempton and that he has a good set of rides, then there is every chance to buy and make a profit. If you think a high profile rider is over-rated and will not be too bothered about busting a gut at a poor midweek meeting, then sell. Again, points are awarded 25–10–5, with a handful of the most popular jockeys being quoted.