They didn't have any music up at Shirley Heights on the Thursday that we were there. I would have loved that. We left St Johns at 5PM and arrived in Philipsburg at 7AM. Our chart plotter was alerting us of a buoy somewhere on our course. We passed within a mile of the "object" but never saw anything. Otherwise it was smooth sailing with only a few other boats ever in view.
The only buoys I can think of offhand on a rhumb line would be the ones off St. Barths delimiting the nature preserve and I'd be less worried about them than the rocky islands that they are close to
I have never been to Philipsburg from the water - so far just outside the lagoon on both the French and Dutch sides. Congrats on a great trip!