We're having a custom island range hood fabricated for a stove top that measures 59" x 25 1/2". Everyone we've talked to suggests going with a hood slightly bigger than this so we were thinking 64 x 27 or 66 x 28, something like that. The hood will be connected to 1500 CFM external blower with 10" ducting which should provide plenty of suction.

The challenge I've discovered is that there are not a ton of island hood inserts in sizes this large so I don't have a ton to choose from. The majority are several inches smaller than what we were planning for on the hood. For example the BEST model is 58 3/8" x 22 1/2" so 6 inches narrower and 4 1/2 inches less deep than what I figured the hood should be. Will this matter? The fabricators can easily pad around the insert with metal to make it looks seamless but I want to make sure it will do it's job efficiently. If the insert is smaller like this, does it even make sense to go that much bigger with the hood? Or is the effect wasted on it?