I will participate in the battle of Osgiliatha althought the game table will be smaller and the points reduced:
Size 4'x2', Points Good:Faramir + Rangers of Ithilien + Osgiliath veterans + 1000 points
Evil: Winegd Nazgul-Witch king of Angmar + Gothmog + Mordor:1200 points Fallen realms:200 points
As I will use good here is my army for the event( Minis not mine):
( As battlehosts are allowed I took Faramir rangers )
Faramir
Rangers of Ithilien 4c.
Rangers of Gondor 3c.
Rangers of Gondor 3c.
---------------------------------
Legendary formations
Osgiliath veterans with hornblower 4c.
Rare formation
Avebger bolt thrower 2c.
Common formation
Minas tirith warriors 4c with banner bearer
Minas tirith warriors 4c with banner bearer
Minas tirith archers 3c.
Minas tirith archers 2c.

1000 points exactly, 9 formations, 29 companies
What do you think?

Are you allowed to take Minas Tirith Knights, it would be a good ide if so, and you probably don't need any banners.

_________________
"I am the Flying Spagetti Monster. Thou shall have no other monsters before me"
-FSM.

I think banners will be very useful as I will have to take panic tests for sure...
Knights may be useful... What about this:
Faramir
Rangers of Ithilien 3c.
Rangers of Gondor 3c.
Rangers of Gondor 3c.
---------------------------------
Legendary formations
Osgiliath veterans 4c.
Rare formation
Avebger bolt thrower 1c.
Common formation
Minas tirith warriors 4c with banner bearer
Minas tirith warriors 4c with banner bearer
Minas tirith archers 3c.
Minas tirith archers 2c.
Minas tirith knights 3c.
1000 points exactly, 10 formations, 30 companies