So the first thing is the size of the canned lights? A 3 and 4 inch may seems nearly the same but have large differences. My living room can be well lit with four 4" angled canned lights and its about 12 x 16. If these are 2 inch cans you are probably good. But at 3 and 4 inches, you may want to change things up. I would do the three lights over the island, one on each short side of the island (depending on size of the space/room) and evenly stagger 3 in front and three behind and use shelf lifting to accent that area. But its all preference and size.