I used a "roto zip tool", which is a big drill but uses a special bit to cut holes in just about any material known. check out lowes or home depot, you just have to push the zip tool bit thru the material, then work it like a jig saw, great for sheetrock, etc., but different bits are available depending upon the material you're cutting. You don't really need to cut the hole that big unless you don't have access to eave from inside the attic and need to install the junction box in the eave from the outside. I had room in my garage to access the eave from inside but that's because this garage is not finished on the inside, exposed studs. Seems like you would have access to the eave from the attic since you are going to run the wire from inside I assume. another option would be to mount the flood ligths on the exterior wall and along with junction box, would just have to use those nicer looking outdoor boxes mounted up close to the eave and just run the wire down into the nice looking box. my .02.