I feel your pain SB, Ive made big win bets on value horses and then didnt play exactas with the likely winners and missed some big tickets.
Perfect example for me is the Jane Cibelli running today; Cherry on the Top.
I bet her to win in her spa debut at 23.80-1 and didnt protect with the Rice favorite in a turf sprint.
Exacta paid over 100 and she paid 18 to place...felt like the biggest idiot of all time. Sometimes with a longshot, the worst thing you can do is ONLY make a Win bet. Best of Racing Luck the rest of the meet!