As long as you come close to break even the DP will be a good deal. You can do this by using TS credits for B, L or D and the same for CS.
I think if you try to "maximize" savings you do yourself a diservice and maybe not book the meals or select the entrees you actually really want. Don't convince yourself that the most expensive are the most satisfying, that mayvery well not be the case.
We used our credits for all three meals, ate plenty, didn't walk around hungry and even had CS credits to use up on the last day (we shared just about every CS meal, we used what was left on the final day).
Keep in mind if you book TS past 7pm you'll still get the benefit of those "shorter" lines as most families with young children head out for their dinners between 4-6. At 7/8 many are returning for the night time parades or fireworks.