I believe one will see a difference in what sort of favs win depending on price range & field size.

Example
All Favs approx 30%W Plc 62%
This includes odds-on horses which on their own win 55% of their races

Favs 1-7 runners 40%W SR

Favs priced $2.80+ = 24%SR
This is the value range one likes to hit upon.
Any less & it starts to get really hard to pull a profit.

Favs priced $4.70-6.00 18% W SR
These can make for good laying possibilities.

Favs in 9 runners & less 70%Plc SR
Delete females that are competing against males & are Fav 75%

If one were to back all Favs in races 1-7 priced 2.90 & less & deleting the competing females , it shows a slight profit.
Any more & it shows a loss.

The Fav will run 2nd or 3rd 32% of the time .
They percentage between the the two varies slightly month to month & year to year.

Favs in Maiden events who are having their first career start have the highest W% of all ... weird.


Check out the interactive UK site by Adrian Massey (Google) where one can crunch some ideas.

Maybe try & break up ones research over field sizes.
1-7
8-9
10-12
13-15
16-20

Its all very well to get a SR on a fav.
Its another to get the price you fell you need to back it.

Cheers.

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Cheers.