At this point, he's got you SO well trained! All he has to do is fuss, or simply wait and, bingo, here comes the dry food. Every single time. You have trained a monster but good!
Next time, put the wet food out for an hour. Pick it up. If he doesn't eat, too bad. Do NOT put out any dry food. Let him be hungry. It will surprise him and make him think. It will also make him hungry. Next meal try again. I don't want him to skip more than one or two meals completely, but still, pick up the leftovers and leave the room. Go do something else. In an hour or so, give him a small snack of dry. Just a little bit, not a full meal. Next meal, try again. Keep me posted on how this is going!
Author Anitra Frazier also recommends just smushing the wet food into the cat's mouth 3 or 4 times at a meal until they "get it."
Another trick is to take a rolling pin and crush the dry food into crumbs. Take a little itty bitty tiny "meatball" of wet food (I mean SMALL, 1/4" across at most) and roll it in the crumbs. Pile up a few of these "breaded" meatballs and see if he'll eat those. The dry food on the outside may fool him, and most of the time, once a cat actually eats the canned food, they realize they like it.
There are also mixers and baby food to "top" the canned food with (or you could try putting a few chicken shreds on top of the canned) to tempt him.
All that said, there *are* some cats who simply cannot be converted. But, in those cases, you are stuck with traditional "dieting" in terms of measuring and restricting intake. Nothing you add to high-carb dry food will make it any better in terms of weight loss, and "light" foods are even higher in carbs. That's why, most of the time, they don't work. In a few cats, sure, but most cats will just gain weight on light foods even when restricted because they go into "starvation mode" and pack on as much fat as possible.
Cheers,
Dr. Jean