I am relacing my countertops with Granite. Problem is I have a center island that is currently butcher block and it has a 29" overhang on one end that we currently use as a breakfast bar. I'd like to have the same dimensions with the Granite but I keep getting conflicting information as to how much support I will need to make sure the Granite doesn't crack. I plan on installing corbels for support. How far out do they need to be to give proper support?