Vals Sills

For this project, the objective is to remove 4 existing window sills on some large windows and replace them with marble sills.Here is a starting photo, and all the windows are this size. On this particular unit, I am also replacing the window mulls and the sill stops.What they look like to start...

Here is what it will look like with the old sill out, and the marble in place. There is a seam in the middle. I am adhearing the sills in place and joining them together at the seam with 100% silicon adhesive. This particular marble looks almost exactly like the Silestone countertops in the kitchen.