Bob graciously volunteered to make a spacer for me so I was planning on disassembling the roller and making drawings and taking measurements (Thanks Bob!). I was pondering the fact that the roller rolls free until the last bit of torque is applied - and was looking at the roller assembly and then it hit me, "Why don't I just sand one side of the wheel just a bit and see if I can make the current spacer work?"
So I worked the wheel on the sanding pad until the wheel spun freely. It took a few iterations as I didn't want to overshoot the sanding.