Mark spent a couple of hours removing wood from the braces today. It’s not finished, but he tells me that the Chladni modes are indicating that the top plate/bracing balance is “good ”.
The ring and a half mode is well shaped with crisp node lines that form up with fairly low power input from his signal generator/frequency counter. He feels that the frequencies are still a little higher than he wants to see, so he will be removing a little more wood in key places to bring them down while hopefully, retaining the overall balance.