Yes.

Have your fabricator remove the tool marks from all shelf/bench edges, even those unexposed to avoid stress risers. He doesn't have to polish them, but no rough edges anywhere.

Fabricators can thin down a 3cm remnant to make a 2cm shelf. That's what our fabricator is doing now for the granite shelves we're putting in the shower niches.

Kid,

The 5.5" comes from the fact that the shower tile itself and the thinset it is on has some thickness. So, I assume he is putting in the bottom granite shelf, and then tiling after, so 1/2" or so will be under the tile in the back of the niche, and another 1/2" or so will go past the tile on top of the cement board on top of your 2X 4's at the side. Your top shelves probably won't be as deep unless he also plans to have those stick out pass your walls. (I am assuming there will be some overhang of the bottom granite shelf)

Glad to hear 1/2" is thick enough for a shelf. I'm not sure if I'll go with the HD tile. My contractor seems knowledgeable, but I doubt he would do as good a job of cutting and bullnosing as a granite store would. What I might do is buy the tiles from HD and have a granite shop cut them and bullnose them.

Fabricators can thin down a 3cm remnant to make a 2cm shelf. That's what our fabricator is doing now for the granite shelves we're putting in the shower niches.

I asked about that at a couple of granite shops and was told it can't be done. They said the granite would likely crack. It may be OK for some stones and not for others.

Have your fabricator remove the tool marks from all shelf/bench edges, even those unexposed to avoid stress risers. He doesn't have to polish them, but no rough edges anywhere.

I'll ask about this.

Thanks for all the replies.