Oh, right...'the effect I'm working toward' but which i did a poor job of doing at 6 this morning
It's the grassland terrains interaction with many types of other terrain types ~ other grass, grass jungle, grass forest, grass forest hill, grass forest, plains, plains hill, plains hill forest, plains forest, et cectera et cetera ~
however, i did a poor job of spacing which is quite evident since most the terrain i wanted to hide ended up begin revealed. I had all the tiles on "reveal tile" on WB, but it kept it under the shadowed FoW ~ hence the settlers and hence the overexposure as it were.
Once i work out the particulars and specifics and the nit-bits and itsy-bitsy's and the..
ahem
once i work it out, i'll then just be a small matter of painting EACH OTHER terrain combo on the intital grasses

a very small matter