but with Tokamak, you can do for sure..
Tokamak has a maximum terrain size of (If I recall correctly) 64 by 64. This doesnt mean that you cannot use it on larger terrains, just that you have to make sure that each seperate map terrain "segment" is less than this.
Obviously Tokamak will accept larger terrains, its just that to correctly know where the surface is, you need to make the terrain have the same hightpoints as tokamak.