The soundboard is Master Grade Sitka Spruce. Came in rough at about 3/16" thick. I glued the book matched halves together the cut out the oversized outline on the laser. Next I ran it through the thickness sander to 1/8" thick. Then back in the laser to engrave for the inlays and cut the sound hole. I relieved the portion for the tail trim with a small router plane. I cut out the inlay bits on the laser .003" oversize to accommodate the laser kerf and glued the one by one into the engraved rosette. Glued in the hoops around the rosette and the tail trim, ran it through the thickness sander again for the finished surface. Looks like the laser burned a little deeper than I planned so I'll add a thin reinforcement ring under the rosette.
Don't know about a traditional rosette, but it seems to be prevalent on 19th century instruments. The grading system comes from the supplier. Master grade is their best stuff.