yes it fixed the road issues by a big time... yes im aware that you cannot use Landbuilder its only in the DeveloperKit which can be bought with license.
For a map with 4096x4096 and terrain grid 8 i picked 32x32m for the Texture layer and everything is OK now.
Just for example if you have map 5120x5120 and terrain grid 10x10m resulting total grid ot 512x512 you will have option for the texture layer 10,20,40,80,160 etc...then you have to put 40 and all will be OK with the roads i guess...