Why dont you just use the Betfair Fav & be done with it.
Its considered to be more consistant than the TABs.

You will notice that the TAB will often mirror the Betfair fav, even after the race has jumped ,when its too late.

Sorry , it appears you a frustrated about what Fav is a true fav . Why.

You may notice, generally speaking , most punters feel that any fav that does not win, is presumed to be a false Fav.

I feel the Betfair Fav is the stronger way to go .

You can use the Betfair site to compare all the live TAB prices with the live Betfair prices at a single glance.
If you wish to follow a TAB price , generally ,its the TAB holding the most money that tends to be the more accurate .
Its all there on that site.

You will be laughing like a Hyena.

__________________
Cheers.