We've spent years perfecting this system and stress testing the heck out of it. We've found that even our 1/4-inch thick wooden inlays were sturdy enough to hold large cracks and correct major shifting in slabs. We've seen customers use a second (or even third) inlay stacked together to give more strength or piece-of-mind, with some even adding an aluminum inlay for the gnarliest of cracks. For those that prefer the look of full-thickness inlays in a slab project, then we simply recommend stacking inlays to give the desired look.