I wear a cape all the time fall to spring, wool coating lined with anti-pill fleece (1 layer each). It blocks wind just fine, rain/snow proof to a decent degree. The holes /edges I guess in your case are where the weather gets in.

As for the sewing, consider hemming (ie, on the bottom) each layer separately and sewing the other sides together. Then flip it right side out and tack it a few places on the bottom. This solves the problem of having to flip the whole thing through a small hole, and helps it hang nicely. Hope that makes sense, hard to explain it in words.

Fedora on my regular laptop, Debian on another, and Bodhi on this HP all in one that someone gave me. Twenty years ago I loved the experimentation and played with Red Hat and SusE and now I just want everything to work without spending hours figuring it out. So nowadays I just experiment on non-critical equipment, like the HP all in one on my kitchen table.