Thanks - What about where the tile meets the units though? and the internal corners? As others have said, I think using the same colour grout and Silicon (mapei grey), with a few attempts i think can get it blend in somehow.
For me I would use the white on internal corners and against the units. Reason being, because of the bevelled edge on the tile the thickness of the bead will change each time it changes angle. It will really stand out, grey over white, the white would be less noticeable.