I am starting an alliance where you can only have one city per member.

With this in mind I will need as many barracks as possible.

32 Squares...

1 Academy
1 Rally Point
1 Feasting Hall
1 Beacon Tower
1 Embassy (unless you can host an alliance without one - i.e. build it use Ritual of Pact and then burn it to the ground with no problems)

Leaves 27/28 Squares

I was thinking 4 Cottages and the rest barracks...

4 Lvl 9 cottages = 18k pop at 0 production and 0 tax - enough to get troops

And I am sure I could farm enough resources to cover building/maintenance costs...

Thoughts, comments?