I love padding borders and edges, etc. A technique that I use an awful lot is to satin stitch over this cotton rope. I know that a lot of folks don't like that much padding but I LOVE it! My best guess is that the rope I have is probably slightly larger than 1/8-inch. It seems to be just right to create a raised stitch at least 3 threads wide although you can certainly expand it over 4 or 5 threads easily as you'll see in the DG ornament below.
Here are a few places that I've used that technique:
The purple border is rope covered with Neon Rays.
This giant curved border also same rope covered with two colors of Flair.
This is my most recent project:
Crazy awesome neon Sparkle Rays over the same cotton rope.
It's just so easy to control and conform to any shape. I like that it's cotton and therefore has a little bit of grip....it's not slippery at all even when using Neon Rays. That is super helpful. I love that I can contort it instead of having to stitch long padding stitches anchored through the canvas which makes curves so much easier and smoother-looking. I don't plunge it through the canvas or even tack it down...just start covering it. It stays in place and is easier to manipulate if you don't attach it. Just trim the ends closely and add a couple stitches to cover and you're done! It's wonderful and one of my favorite things to add to a canvas to give a little dimension and add visual interest.