Best way to wage war is to not have a special 'war city'
Just cap npc10's and jump from 1 to the next to the next to the next every 10-12 miles apart to get from red flag to red flag to red flag. Works nice and in 3-4 hours you can wipe out 2-3 enemies from 1mile out.
Ofcourse this works better with a big hero.
