Such large tiles have to be precision-cut for installation, which is hard to do without professional, large, expensive tile saws. This instructable shows how to cut these tiles using a tiny hobby diamond saw.
Step 1: My Tiny Hobby Diamond Saw
First problem is that the tiles are much larger than the table; I fixed it by laying a piece of plywood with a slot for the diamond blade. I plunge-cut the slot with a circular saw, and attached the plywood by driving drywall screws from the top, through some holes in the tile saw's table into a piece of lumber underneath.
The second, more serious problem is that it's hard to make long, straight cuts with this setup. The diamond blade is very unforgiving of side loads, and will bind unless the cut is very straight. It's practically impossible to feed the tile by hand into this saw in a straight line, so even if the tiny electric motor didn't stall the cut would be ragged. This instructable explains how to set up guides for perfect cuts.
Step 2: Setting Up the Guides
For the guides, I am using fairly thick plywood and hardwood pieces---nothing fancy, just pulled out of my scrap wood bucket. They just need to be straight---look down the edge to check for straightness.
First, I clamp the helper guide to the diamond saw blade, as shown in the first picture. Wiggle the guide to find the best centerline---this is the kerf line. It may help to mark it on the table, but the alignment is best done against the side of the guide. It may help to clamp the helper guide to the table (I didn't do that in the picture).
When the helper guide is set up, we configure the first guide, offset for the correct cut distance. Again, it has to be exactly parallel to the kerf line, so we need to measure the exact same distance from both ends of the helper guide. I don't trust the tape measure for that, so I used a caliper. Make sure to measure from the side of the helper guide that touches the saw blade---that's your reference.
Remember to take the kerf width into account---it's possible to get sub-millimeter accuracy if you're careful.
With the first guide in place and clamped securely, the second guide is positioned by laying it against the tile stacked against the first guide, as shown in the second picture.
The tile should slide freely between the guides, with neither binding nor noticeable side play. Given that, even granite and porcellain will cut easily and smoothly. The entire tile can be cut in about 30 seconds, with minimal force.
Look at the smooth kerf in the third picture! Success again!