Which favourite is your system backing?
You built a system on the favourite. Roughly one race in twenty, it is not the horse you think it is. The video shows why, and which rule to use in the System Builder for each meaning of "the favourite".
SP or Betfair?
In the System Builder, Favourite Status means the favourite at the industry starting price (SP), not at the Betfair starting price (BSP). Usually they are the same horse, but not always. In the 15:15 at Haydock on 26 September, Angel Gabriel was the SP favourite at 100/30, while Rousing Encore went off favourite on Betfair.
The four boxes
Add a rule, open the Market group, and Favourite Status is there with an amber dot: the figure only exists once the race is run. Pick it and you get four boxes: Favourite, Joint Favourite, 2nd Favourite and Joint 2nd Favourite. Tick Favourite alone and every joint favourite is left out, so if you mean the favourite, whoever it is, tick Joint Favourite too. And the boxes stop at second favourite: the third horse in the betting is never marked, so this rule can't reach it.
Ranks reach any place in the betting
SP Rank orders the whole field by starting price, with joint favourites sharing first. BSP Rank does the same on Betfair, so BSP Rank 1 is the Betfair favourite, and 2 or 3 reaches the next ones in the betting.
Settled at the off
Favourite Status, SP Rank and BSP Rank are all settled at the off, so the Qualifiers tab skips them. On its own, a system built on them can't pick out today's runners: the Qualifiers tab shows a note instead of a list, and the rule carries a warning mark that says why.
A list before the off
For a list before the off, rank on a price that exists before the off: Evening, Breakfast or Morning Price Rank. Set Breakfast Price Rank equal to 1, and once the breakfast prices are in, the day's breakfast favourites fill the Qualifiers list. It's a different question, though. About one race in three, the breakfast favourite isn't the horse that goes off favourite, so back-test it on its own before you trust it.
Search by what you mean
You don't need a field's exact name. Search Betfair in Add Rule, and every Betfair starting price field comes up, BSP Rank among them.
The System Builder is included with RaceMetrics Pro and Proform Premium. See the plans.