Order shutters for the smaller size to avoid any trimming. This will result in some light seeping in through the gaps where the opening is larger. Small wooden strips can be tacked to the inside of your opening, just behind the shutters, to prevent this. Having an overlap rabbet where the shutters meet will also keep light out. As all windows are a different size we do not make stock shutters.
Every shutter is made for a specific opening for each individual order.
This means our shutters are custom sized and this allows you to have any number of individual shutters within an opening that you would like. If not, you will most likely not have reason to open the shutter frame often except to wash the window glass. This would be a reason to go with as few shutters as possible. This will maximize visibility and minimize costs. This will help to determine the maximum size of the individual shutters.