Great to see development of the troughs over time. I have had similar experiences with plants of mismatched vigour! I find it difficult to site Kabschia saxifrages as they scorch very easily here but without enough sun they don't flower well. I wonder if the Saxifraga cochlearis minor in your trough is actually Saxifraga paniculata minor, I do not find the Sax cochlearis over-vigorous, the plant pictured below is perhaps 10 years old. Nice to see the globularia in the last shot, reminds me of Globularia cordifolia which I photographed in the Alps on the day the Log went live!