I do everyonce in awhile.
My modus operandi is
i.e Take the case of Seymour R 7 H 1 - 5 - 7 - 9 - 13 I exclude all horses under $6 (add 1 to the number of selections for MINIMUM acceptable Price)
Whats left I box up for the 1st 4.
If whats left are too few then I either take the Quinella or Trifecta .
Ocassionaly I get a massive payout but rare.

I like your thinking.
My selections I get from the Don Scott weight ratings at R+S.

Good luck today.
darky