dedicated server with world composition questions

We are working on a multiplayer game.

We have a large map setup in world composition on a dedicated server using sub levels to split up the landscape. Each sub level content models and objects, and trees and grass and foliage. The persistent level contains stuff like the sky dome / sky weather / day night system, ocean, and our weather trigger volumes, etc.

We were looking at adding another section of the map (we only have 1/3 of the map created atm) when the question came up about performance.

what are the pro’s and con’s of these 3 separate configurations:
1 - Build 3 projects each with 1 map
2 - Build 1 project with 3 separate maps in it
3 - Build 1 project with 1 large map

We are mostly concerned about server loads and the larger map sizes.

Any information would be useful.