Hi
I think you may find the larger tiles have warnings not to exceed a 30% overlap to prevent lippage.
See pg 11 of https://www.porcelain-tiles.co.uk/wp-content/uploads/pdf/guide/Porcelain-Tiles-Installation-Guide.pdf.
Out of interest, has anybody tried ordering tiles from the internet website Tile Expert? I am considering using them, but wondering what their customer service was like.
Thanks