I have 13" deep cabinets. We installed wood behind the vent to pull it out about an inch, making sure that we mounted over studs and then mounted the vent to that. We had a metal shop cut a 2" strip the width of the vent and then bend it at 1" so that it covered the wood at the gap and then tucked up between the vent and wood to make sure there was no gap. The tile splash covers the back edge. You could do the same thing, but would need a wider trim strip. You could also do a custom hood.