>>1231562>>1231830/diy/ here again.
I saw a scrap piece of flashing laying around the shop and decided to whip up something. There's no need for any extras or have normal holes. This style works perfectly. If you can cut tabs in titanium sheetmetal then you are good to go. For the air flow, I made 6 half circles, 3 top and 3 bottom, using a quarter coin for general shape and size. The paper binder clip idea is also confirmed to work.