Which is better nap 10 or nap 15?

A NAP is very useful if you want to work together as a state and concentrate on competing with other states in Clash of Zones or doomsday events. The number of alliances to include It will depend I guess on how many big alliances there are in the state and whether you still need to be able to attack some other bases. Many players these days set up farm accounts and alliances to feed from and the NAP can extend to almost all alliances in the state.