Grippers, suckers, sticky mats, etc have never been any good with any of my three. If anything, the fact that the bowl or plate resists them is even more of a challenge! Once they're more interested in eating than in exploring, then these gadgets can be helpful. Ds2 is 11m and still gets his food either given directly to him or a few bits placed on the highchair tray. Ds1 and dd were well over 12m before they could reliably be given a dish with more than 1/4 of the meal on it at any time.