I used to work at Joe's and i did a fair number of the snapped boards. Never used dowels. Figure the dowels are harder than the foam and would just wobble and route the foam with enough force put on it. Did use a super thick batch of cabosil, pretty much putty consistency and held it with clamps to make sure the rocker was correct. Add several layers of cloth that extend a good way each side of the break and its off to the sander.