I like to look ahead the number of spots til my next pick... in your case 3 and 21. Although the number 3 is a little small... so I'd probably use 6 (half of the number of teams) to be safe.
I also like to look ahead 2 times the number of teams, just so I don't miss anything. I agree three times the number of teams might be a little overkill.
By looking ahead 24 picks, you are saying which player has the best value on the board over the next two rounds. Then set it to how many picks til your next pick (no less than half the number of teams), and see if that player is still going to be around by the time you pick again. If so, you might be able to wait on him and grab another top player. If not, then you should grab the player.
With running Mock drafts with the Dominator, it is hard to see any real value in the players, because it is picking against itself. But put it in a room with guys that are using outdated magazines, and cheatsheets from other sites, and you will see it shine.