A Pick 3 Lesson for me

Hit my first and only pick 3 thus far at Retama. Paid 170 bucks.

5th race I take:6,7 These 2 horses are favorites at 2/1. The 6 wins.
6th race I take: 7 The 7 is a 2/1 favorite and wins.
7th race I take: 1,2,7 respectively, the public makes them 2:5, 9/2, 8/1 The 2 wins at 9/2 and it is a two horse race the whole way with the 1,2 doing battling. I thought this would set up the 7 but it was not even close.

So we look at this and say very chalky. I really needed the 7 horse in the 7th.

My hypothesis and possible plan. Races that you know people will single will have larger pools imbedded in them in Pik plays at small tracks. The public needs some race for a shallow water single. Always include a race you think is everyone else's clear single and go deeper, especially if there is ONE worthy opponent that just might give the favorite problems. I still would have won a little something, even if the 1 horse had done what he was supposed to in the 7th. Someone else may have already brought this up. I apologize if they have, as I dont play pik bets very much.

Scuds or any other pik players, feedback?
Have I found an in? Any help appreciated.

BTW. The pik 4 that included the 6,7,8,and 9th races paid 148 and the even money favorites won the 8th and 9th. Again an example of the unknown pool size, and a possible reason for the above and the attempt and reasoning on how to get into a large pool with a few winners without knowing what in the hell is going on. Did one of the favorites in the 5th race at 2/1 make that big a difference... Jeez, who would have ever known.