Gauging interest in a server hosted campaign world

[Aaron]

For an observer on the ground with eye level at h = 5 ft 7 in (1.70 m), the horizon is at a distance of 2.9 miles (4.7 km). For an observer standing on a hill or tower 100 feet (30 m) in height, the horizon is at a distance of 12.2 miles (19.6 km).

So 15 miles is too much? Take it down to 12.2 for best conditions?