Not quite in line with original idea, but I have just ran a test for all days this month so far every venue, first 3 races targeting final SP fav.

Races Bet: 382
Races Won: 159
S.R./Race: 41.6%
% P.O.T. : 4.7%

Best day by far were Sunday and Monday

Sunday 96 bets for 43 winners strike 45% 5 OUTS 12% POT
Monday 39 bets 18 winners strike 46% 3 OUTS 33% POT

Sat showed 96 bets for 41% strike and 12 OUTS 4% POT

Also food for thought.

Enjay