Eyeballing is a visualization technique. The stadia method is a visualization technique. The big difference to me is the degree of precision that I'm attempting to achieve.
Eyballing compares the target/feature size with your angular field of vision. Bracketing compares target/feature size with a graduated angular scale (stadia marks or mil-dots).
In my field of vision, the less area covered by the target, the farther the distance. Across my mil-dots, the fewer dots spanning the target, the farther the distance.
Canadian rules -
If AAFTA Open Division rules were more like CAFTA Open Division rules, I doubt that we would even be having this discussion about Hunter allowances.