I live in California. Most granite/marble/quartz here is 2cm although 3cm can be found. Cabinets have to be level no matter what. I have Caesarstone on my perimeter counters that are 3cm with no laminated edge. My island is 2cm marble with a mitered edge that doubled it to 4cm. My butcherblock counter is about 1 1/2" thick (a little less than 4cm). So all counters are a different thickness and I don't even notice the difference in thicknesses. I think the thinner edge is slightly more contemporary looking, but it's really up to what you like. Plywood with metal supports on the island before the marble was installed: 3cm Caesarstone (Arctic White), 2cm marble, 1.5" butcherblock:

You can save some money by going with 2cm, but you they will have to "double up" the edge, so there will be a seam line where the two pieces join. How noticeable this seam line is depends on the quartz (and the quality of work too, I suppose)- the ones with larger pieces tend to show the line less. I've seen edge joints on counters where I noticed it immediately, and on others I could only see it if I got up close and looked for it.

marissa 16: Estone comes in 1/4" (floors/vertical only), 2 cm, and 3cm. You can laminate the 2 and 3 cm to get to 4 and 6 cm respectively. The appearance of laminated edges depends on the quality of the preparation, the clamping, the adhesive color match, and the color, particulate, and movement of the particular estone. This becomes much more art than science. For the record, I am not a fan of solid underlaymnent under estone or stone, plywood or other; it is too dimensionally unstable and incompatible. Strips maybe and keep it 1/8" away from edges.

99% of all quartz manufacturers will not have 30mm in jumbos. You will have to go into the color you like and see if a jumbo is available on their site The four you have listed there are Jumbos available if in stock.