John,

Certainly no right or wrong way, its about value be it actual or perceived. There are guys that will bet 2K to win on 6/5 and talk about value. That has never been for me.

Look at the Donn, 8 horse field, you tossed 2 of the 8, 29/1 & 2/1 favorite. You're playing 4/1 back and forth with 5 horses all 9/2 to 7/1. Whats the most any exacta you played was paying? Probably 70 bucks so you are getting 5/2 on an exotic bet if you hit it which you did not?

EX: I liked Valid who went of @ 6/1 if I make your wager I hit a $53 exacta and would get 3/2 on my money with a top upside of 3/1. I can't do that so I took a shot played him back and forth with 2 horses and got 12/1 on my investment.
Unless you're playing the grind it out game, I feel the reward has to significantly outweigh the risk.

Now a 20/1 shot in a 12 horse field is an entirely different scenario!

Good luck,

Frank D.