Use white adhesive flex, as said clean it as you go, keep sealing it prior to grouting until it won't take anymore sealer, get the stone in the house for a day minimum before you fix it, as when the dampness comes out of it, you'll see the variations, fissures, stand back from the fixed tiles every 30 minutes, to make sure your variations are even and one doesn't stand out from the other, do not be persuaded to use the wax's that certain companies recommend, as its a wax finish and wears within 2 months, if you can get an even shine on it, improbable !, as the darker ( denser ) parts of the stone appear shinier, and the client then requires an even shine throughout the whole tiles, as it looks smeared, even a buffer will not create an even sheen throughout, so do not use the wax, as the client will have to re wax every 2 months ! back butter tiles and back the sides up, wipe off excess sealer ( as this will cause a waxy build up that will not easily come off, even with re applying more sealer to dissolve it. most important to get the tiles in a dry atmosphere prior to fixing to see the real shading.
