Need some advice on my Ultima Online map

I am attempting to build Ultima Online using World Machine. I plan to shortly upgrade to pro version for use of the Tile Map ability. I have a map where I outlined all the land masses, and started contouring and creating an more realistic size and geology.

My problem is, my current map is bit smaller, where I would like it 4x bigger. I have the main landmass as one object, and each main island as their own. So, any suggestions on making everything 4x larger?
I have attached a file.