Hello Galen, I have just had a new kitchen fitted, our worktops are made of something called "silestone" which is a quartz like material very like granite which we were originally going to go for but opted for this instead as apparently it doesn't mark as much. By overlay do you mean a piece that juts out from the work top to make a breakfast bar so you can perch on a stool and get your knees underneath? If so, yes we had that done and are happy with it. I believe if heavy stone like worktops jut out too far, some sort of pillar like support has to be put in, but we opted to make our bar slightly narrower than it previously was to avoid this but this adjustment has not impeded us in getting our knees under the worktop in any way.