To remember, these are my rough scales:
- 1 month: 48 leagues (consider rounding to 40, 45, or 50) -- ~850 x 1300 miles (empire or small continent)
- 1 week: 12 leagues -- ~215 x 325 miles (kingdom)
- 1 day: 2 leagues -- 36 x 54 miles (duchy?)
- 2 hour "chunks:" 2 miles (if you require 2 chunks/day for downtime)...or 0.5 leagues (if downtime is abstracted -- 12 x 18 miles or 9 x 13.5 miles (barony?)
- 1 turn (~10 mins): 1 furlong (220 yards) -- 6/8 mile x 9/8 mile (manor)
- 1 round (~1 min): 4 rods (22 yards) -- ~130 x 200 yards (5 acres)
- 1 segment (~10 seconds): 2 paces (10' or ~3 yards) -- 20 x 30 yards (1/2 rood; about 1/8 acre)
- 1 segment (~6 seconds): 1 pace (5' or ~1.5 yards) -- 10 x 15 yards (perch, or 1/160th of an acre)
There is no good definition of operational level scale. This is the (cumbersome) DOD definition:
The level of war at which campaigns and major operations are planned, conducted, and sustained to accomplish strategic objectives within theaters or areas of operations. Activities at this level link tactics and strategy by establishing operational objectives needed to accomplish the strategic objectives, sequencing events to achieve the operational objectives, initiating actions, and applying resources to bring about and sustain these events. These activities imply a broader dimension of time or space than do tactics; they ensure the logistic and administrative support of tactical forces, and provide the means by which tactical successes are exploited to achieve strategic objectives.
The best, simplest definition I've heard is from Norm Koger, a game designer.
The Operational Scale: A view of the battlefield on a scale just exceeding that at which differing ranges of various direct fire weapons are significant. So, as we can see, the scale of "chunks" is operational, as a longbow's range compared to a crossbow isn't really relevant when hexes are a mile or three across.
But, it does highlight the difficulty associated with this scale. Where exactly does it begin? What should the time/distance units used be? There is gray area on both the tactical and strategic sides.
Its interesting all the grief that Chainmail has caused, as its basically still at the tactical level of conflict. It isn't even necessarily a viable "end game" for D&D. In my opinion, it'd almost be better and easier to have an operational level engine rather than a limits-testing tactical one like the 1:20 scale suggested in Chainmail features.