While I tend to practice the philosophy of Koukovagia, I too am a replicator. In fact, at this moment I'm replicating one of Todd English's sauces. Mine are always good but rarely as great as the real thing. Best technique to get as lose as possible - ask the chef to share the recipe. It might take a lot of scaling for home quantities and experimentation, but better than dealing with vague suggestions and taste memories... Unless you have a "photographic" palate of course!