I can see the value of honing a recipe, as far as learning to detect the subtle changes in flavor small variations in ingredients and process make. The way I brew, it's difficult to discern these subtleties. I never brew the same thing twice, and often measure, crush, and begin mash before I even have decided what to do for hops.
To do what you are doing and get meaningful results however, one should bottle at least a few bottles of each brew, and store those bottles in the fridge after bottle conditioning or bottling from a keg. Making a batch to batch comparison is subjective enough as it is, without taking into account differences due to age. Ideally it should be in the smallest possible bottles.
Comparisons between individual batches may guide you to the next brew, but at some point or points, one should be able to review various batches at a similar state of aging. One needs both meaningful short term guidance and long term review for something like this.
H.W.
