While my go-to spinning is thread, I also LOVE supercoil yarn! I have never knitted with it, but I love to spin it. Rather, I love to have spun it. The plying is quite labor-intensive. I spin a single with extra twist, with thick and thin bits for interest. To ply, I wrap my core yarn or thread around a toilet paper or paper towel roll with a slit at the top, suspend it in mid-air and unwind it as I need it, pausing quite often to let out the twist. This first one was merino/silk from Corgi Hill Farm.
Here's a supercoil project. I started with baby camel/silk fiber, painted by Zebisis Designs, my favorite dyer in the whole world. This is her photo of the fiber.
I took a braid apart at the yellow and the green and turned it around, so as to do one color repeat, in rainbow order (am I predictable or what?).