That Problem Solvers variable spacer is a neat solution but, the web site doesn't say what diameter(s) and I assume it's 1-1/8" only. I also assume it works well on the correct diameter steerer.

Years ago Easton included a variable thickness spacer named the "Beartrap" with their all-carbon forks. It was a pair of ramped rings with the ramps facing each other and a bolt that rotated one ring relative to the other so the ramps climbed each other and increased the spacer thickness. Here is their instruction sheet: http://www.eastoncycling.com/bike/wp...eartrap-EN.pdf

It was a very neat idea but, unfortunately, a failed design. The adjustment wouldn't hold and the rwo rings rotated loose from vibration duing every ride. Easton soon dropped it. I had two of these that accompanied Easton forks and Easton sent me replacement standard compression plugs at no cost when I called to ask why I couldn't get the Beartraps to hold their adjustment.