I worked last year on 4 quilt tops from feed sacks. Then I had about 40 blocks I took those & sashes them they were uneven to but hand sewn I made the sashes larger than I wanted so I cut square up the block when finished the way they are squared it looks like the blocked is straight . Just an illusion to the normal eye. Worked quite well. Play around with uneven ones . Try different ways maybe to thin sashes will help. Good Luck I felt so humble sew mine they were so old and the hand stitches were beautiful they were done by my family .