You might try tightening your wire so it fits very snug against the "outside" teeth. You don't have much room in the channel to prevent your coil from touching the wall. One trick is to helping remove them when the wire is tight, is to first line the bed with two pieces of wire, keeping them straight, running them down the inside of the brush close against the teeth. When you invert the brush, you can pull straight down with those two pieces of wire which will pull the coils off the teeth. Red wires below being under the coil wire to demonstrate.
View attachment 615911
I cheated, and took an old piece of mesh, put holes in it to match the teeth. I then slip the mesh piece over the brush, wrap my coils, invert into the pancake, pull on the edges of the mesh and it pulls the coils right off the teeth. I could get some tight wrapped coils that way.