I did this mod on a GT Double today, using 1/2" pvc and gmctr's buried Amsteel to secure the bar. It does, indeed, eliminate the calf ridge.
The pvc seems pretty heavy to me, so the dowel may be a better choice.
I am concerned by a couple of things, the first being the sharp bend in the Amsteel where it exits the bar on the hammock side. I don't see a fix for this, other than building in some security with 1/8" Amsteel. The other areas that bother me are the entry/exit points where the buries secure the bar. The Amsteel loop is deformed there to an unsettling degree. The shorter buried piece is there to take some of the load, and as a "safety net", so that mitigates my concern somewhat, but still, none of us would be comfortable with a whoopie that looked like that. Right now, I'm leaning toward a stopper knot of some sort, instead of the buries. Thoughts?