The Britannica slab above was a 3 cm slab. But either 1 or 2 cm could work just fine and not be a quality issue if they support it underneath. It's more of a design preference. If you are laminating the edge to make it thicker than 1cm you can achieve whatever thickness you like. This island above was fabricated without matching veins even though it looks like it. The full pattern is on the top and a well placed close match was done at the waterfall. If you have a fabricator that uses a fabrication visualizer tool to lay out the slabs you could explore this option of using 2 or 3 cm and not bookmatching. Hope this helps!

Very helpful and thank you for your quick response! Yes, we are laminating the edge and will have 2.5 inch edging around the whole island. I was worried a 1cm slab would be less durable, but your answer helps me make my decision. I saw the 2cm slab design for waterfall and didn’t like how the veins matched, which is why I’m now considering the 1cm slabs.