Now here is where I would do some different experimentation. But, perhaps the gun owner has already tried\done this. If the Limbsaver is working to reduce groups when it's at that point of the barrel, then why not take either a chunk of the Limbsaver, or just rubber, or some other material, and place it in between the forarm and the barrel in "given" places.
Take the same methodology that Limbsaver uses and start close to the receiver, then move towards the end of the barrel. This will have an effect on barrel harmonics while having no effect on aesthetics of the gun.
Yeah, it will take some time to do this, plus some ammo, but if it works....you won't have Rosie O'Donnle hangin off your gun all the time either.
And if it doesn't work??? Well, then it doesn't work.
Dave