Mike G: Nice work, glad I could be of some help. I don't think the retaining walls are a failure. I think you need to weather them, and consider replacing the top cap with a "concrete" or "slab stone" cap. I am attaching a word document to this post that contains all my notes from when I weathered a long concrete retaining wall, and my Pennsy Stone Block walls which are very similar to your casting. There are some photos attached below, which were done with the technique and colors described in the MS Word document. I learned in the last 2 years that I needed to write down what I was doing if I was ever going to have a prayer of duplicating the same effect again.
The first block wall photo was taken before the final diluted acrylic wash was applied.
