Grouting Chiselled edge tiles

I've received samples of the chiselled edge slate tiles and we love them.

I am unsure of how to lay them because of the angle and thickness of the edges. Do you butt the tiles up to the next or leave a very small gap as a grout joint?

Always leave a small gap between the tiles for a grout joint to allow for expansion (especially if using an underfloor heating system) and grout using a flexible floor grout.

With this type of tile it is important not to overfill the grout joint, as the edges are very irregular and deeper in places, overfilling will result in some joints that could be over 10mm thick.