I've installed a few of these KitchenAid cooktops. The suggested method for securing them is....well... stupid. They supply these big brackets you're supposed to secure between the deck and the countertop and then there's a single screw that goes through the bracket and then gets driven into the bottom of the unit, clamping it to the counter. The problem is, the brackets are none too stout and rarely stay in position when the stone is set down on the deck and they hang down so far below the cooktop, there's no room left for a drawer underneath.

I like to get the unit in position and squared up, then mask off the counter, pop the unit out and lay down a thick bead of silicone 'inside' the tapeline, then set the unit back in place and press it down firmly. A good cleanup with some towels and Denatured Alcohol and then let it sit overnight.