Creating big world (double precision)

Hi, i am currently in the Main-Branch (current as of 1/23):

from what i understand LWC is enabled by default now? UE_USE_UE4_MAX_WORLD_SIZE = 0 (i have confirmed that this was so in the code),
however i am getting a failure from D3D12Texture.cpp on landscape generation, it appears it is using int32 Float.
is there something additional i need to do in order to enable the double precision to be used?