Last week I spent 8 hours patching several pieces of .020 - that were not big enough - together so I could fit and adjust a top rear skin onto the Fuselage to form a pattern for a new full sheet of .020 I had coming. Where possible I've found it's better if if work up a pattern first than transfer it's cuts and markings to the final sheet. Less waste and it's part of my learning process. Even when I measure 3 and 4 times and cut or drill - the possibility of mis-cutting or mis-drilling is still there. If I work with a pattern of scrap first then I cut the waste way down. Spent a couple of hours today transfering the cuts and holes to the final sheet and readied it for installation.