One-for-all: Everyone makes their own units and resources but work together in wars to try and win.

This is good for pacts full of pretty active people, or for pacts with members that are online at similar times.

Each person makes their own units and resources but together with their pact mates they declare on their targets with 2-3+ members of their pact to increase their chances of winning.

Its a good idea to have each member similar in land.

Also when a person is declared on in your pact, several of your pact members should declare war on the person who is attacking their member.

Safety in Numbers is the key philosophy here.