The moisture absorption might be an issue. I used lead weights (free from my local tire store) and added sand.
JUST AS IMPORTANT as the material is the level of fill. I experimented with quarter, half and all the way filled. Surprised at differences, settling on about 2/3. Clearly, like everything else: try and experiment.
JUST AS IMPORTANT as the material is the level of fill. I experimented with quarter, half and all the way filled. Surprised at differences, settling on about 2/3. Clearly, like everything else: try and experiment.