I am doing the kitchen floor with diamond checked layout in black and white without the border and initially thought I chose the exact same size tiles 333 mm X 333 mm. However when it is matched against each other, white tiles are bigger than the black tiles by about 3 mm. Tilers are refused to lay it because of the large variance and the effect of the grout around the black tiles will be inconsistent to that of the grout around the white tiles. It will look a bit zig zag and not straight when you look at the entire finish. Anyone? Please help me. Thanks.