the whole map (including all the islands) works out at 96km x 96km and working on the basis of importing 2km tiles.
I’ve had to make a couple of compromises with size.
Eventually I plan on importing into the whole thing into Unreal Engine. I got all keen and splashed out on the professional version to try and build my own reimagining of Britannia based on the UO map. I’ve only really just been dabbling with WM until I started on the same thing.