Probably it is already late for this answer, but, if you are putting the fridge under the counter as I did, the best way to do is as follows. Dont build a close Keg box for then to cut it, Just leave the side open, measure your fridge for the opening if it is close enough let say .5″ all the way around that´s finel, actually from experience if you are going to plase your CO2 Tank outside the Keg Box as I did, this space it tight to fit the CO2 line thru. One thing I recommend is to have the frame of about 3″.4″ aroung the frame as indicated in the plan, this will provide a support surface for the foam. After you fit in Electric power Wire, Power Source wire, CO2 line then all you need to do is to spray the Great Stuff all the way around the frame to complete it seal it, actually it is better to have around 1/4″ in or more, all the way around for easy access and better foam expansion and distribution to have a better seal and insulation. If you have very big gap to fill you can use poliesterene and then great stuff to seal it. I hope this helps you.