The Size of the Lunar Empire
It is surprisingly hard to say how big the Lunar Empire actually is. There is a good discussion of the problems at http://grahamrobinson.com/glorantha/lunar_size.html. The Lunar Empire appears to be about 1200 miles by 1000 miles in the map by Phil Anderson in 'A Rough Guide to Glamour'. In the more modern map by Wesley Quadros http://www.celtic-webs.com/glorantha/middle/maps/maps.html and the map in the Imperial Lunar Handbook 1 p16 the Empire is more like 600 miles by 550 miles and this matches the map on p16 of the Imperial Lunar Handbook. As Graham Robinson says on his website this doesn't match the description of the distance from Mirin's Cross to Glamour in the Imperial Lunar Handbook 1, p12 as being about 1000 miles (on the map it is more like 300 miles). The map of Dragon Pass, Land of Thunder is 155 miles by 115 miles though this is apparently 10% too small according to the Issaries website. Sartar excluding the Far Place is only about 85 miles by 60 miles (or 94 miles by 66 miles scaling up by 10%).
In comparison with the real world (this is a rough approximation drawing a rectangle around the borders):
In modern Britain: the English county of Devon is about 69 miles by 65 miles. Ireland is about 300 miles by 200 miles. Wales is about 150 miles by 110 miles. The United Kingdom is about 600 miles by 400 miles. France is about 600 miles by 600 miles.
Using ancient examples the Roman Empire at the time of Augustus was about 2700 miles by 1100 miles, the Achaemenid Persian Empire of Xerxes was about 2900 miles by 1100 miles and the Macedonian Kingdom at the time of Issus (thus before the conquests of Alexander) was about 500 miles by 450 miles.
However Gregg Stafford has stated that the scales on these maps are wrong. He wrote in World of Glorantha "Measuring from just south of Wilmskirk to the edge of Snakepipe Hollow, Sartar is approximately 125 miles, and from the Marsh to the edge of Prax, about 100 miles." and also: "The breadth of the Lunar Empire is supposed to be approximately 1000 miles by 1000 miles."
The most straight forward way to sort this out is to double the scale on the map of the Lunar Empire in the Imperial Lunar Handbook 1. This gets it to approximately the right size so that the Lunar Empire is then about 1200 miles (North-South including the provinces) by 1100 miles (East-West including Carmania).
On the map of Sartar in Dragon Pass Land of Thunder instead of adding 10% double the scale too (to be really accurate multiply by 1.7). Sartar is then (from the edge of Snakepipe Hollow to just south of Wilmskirk) North-South approximately 144 miles and (from a line from the edge of Upland Marsh to the edge of Prax) East-West 130 miles. This is a bit too big hence x 1.7 is a bit more accurate if you want to go into greater detail.
These changes make the Lunar Empire reasonably big - about half the size of the Roman Empire. Sartar becomes more like the size of Wales.