I've found the best parish layout for Age IV. Most of the credit goes to ReiAtur, I just modified it to fit more. This Layout concentrates on military buildings and castle structures.
THE LAYOUT
Spoiler! :
1 Architect's Guild
1 Sergeants at Arms Office
1 Military School/Town Hall/Church (Whatever you want from these three, but I don't recommend town hall)
20 Barracks (500 troops)
1 Ballista Maker
1 Siege Engineer's Guild
1 Castellan's House
1 Archery Range
1 Pikeman's Drill Yard
2 Production Guilds/1 Tunnellor's Guild + Turret Maker/1 Guild + Tunnellor's Guild/1 Guild + Turret Maker
or
17 Supply Depot + 1 Stable/18 Supply Depot (There is only 17 Supply Depot and no stable in the image but the other one will fit next to the Woodcutter's Guild)
??? Statues