I've laid tile sheets for my back splash in my kitchen. The tiles on the sheets are not exactly the same by length (in comparison to the corresponding tile on another sheet).
Therefore I have grout lines which are mostly between 1/16" and 3/16" (but not consistently one or the other). There are also some where the tiles are almost touching. Most of the spacing between tiles on each sheet are 1/8" (though they vary as well, mostly larger)
I've read that unsanded grout will sag in a space larger than 1/8".
Which type of grout should I use (sanded/unsanded)?
Also one more thing, the store I bought my tile from sold me a bottle of Flexible Grout Admixture. Should I use this in place of water or is it just a sales gimmick and I should return it?