25x25 in salem is too small, 42x42 is great... I can post town plans today, maybe you can use them.
EDIT:
Town A is town when you add people, on its claim you can build common buldings like mill, smelters, owens etc etc where every town member will have access.
Town B is town where ONLY YOU got your mayor! (you can use base 100x100 claim for your fighters hv or storage).
Trick is that you let people drop personal claims on town B (town where they have zero permissions), when they are not in party with town-b-mayor they can't claim more land, but their plots are still protected by town-claim. Even if you will have two hostile groups in town they won't be able to bash each other wall without waste-claim
You would have permissions to bash anyones wall, even more if you build around each plot make shift fence on town b claim you can lockin people that are making trouble and punish them later.
Of course town B claim can be done with only 32 crosses, so it shouldn't be so hard to pay its upkeep.