I had 3 skeins of this coral-ish, rust acrylic yarn, so I decided to use it as the centers.
The wool is some of the scratchy mystery wool that we tried to dye with natural things.
I started winding centers until they looked about right and went on to the next. I was aiming for 4, and ended up with a little 5th one.
The majority of the centers are 7"
Here is one wound with the wool next to a center.
I got 2 out of each of the lighter colored wools and used the entire red-ish yarn on the smallest center.
I put the dryer balls into these socks to felt them. But it didn't seem to work very well as the yarn wasn't sticking to itself. So I stuck them into mesh bags for a second try
I didn't tie the bags well enough and they all came out! One had its end come loose, but this one was a mess!
This is what they look like after the 2nd washing and drying. The yarn is still not stuck to itself, but they did shrink some.