i wish i could help but the only experience i have with zippers is putting them in dresses or skirts. i have a pair of pants that i would love to replace the zipper on but i haven't made that attempt yet. good luck! i love the jacket, btw.
Often times in the past, I end up abandoning once hopeful clothing projects because I didn't follow directions and have no patience trying to figure out how to fix it. Because I've been making so many articles of clothing the past few months, I'm starting to revisit these sad, sad abandoned and half-finished projects to breathe new life into them. What do you guys do? Do you give up and move on to the next project or try to give them new life?