During the last break in building, I ordered 3 sheets of .025 aluminum from Aircraft Spruce for starting the fuselage. I made the decision to order the pre-drilled skins from ZAC for the left wing - here's why. The cost of CNC drilled and trimmed skins is cheaper than I can get the bare aluminum from Spruce. I figured it would also save some time and boy, was I right. The predrilled skins fit my scratchbuilt spars and skeleton perfectly - I mean down to being able to see a thin Sharpie line through a 1/8"hole over the entire 12-foot span. The predrilling will save me many hours of building. The wing root and wing tip are pre-cut as well. Amazing. I skinned the top of the wing and flipped it to start on the bottom tomorrow.