There are no easy solutions to the barging buoy. I often don't use one unless the boat owner requests it (which is pretty often). The currents here are vicious, placing the boat in weird directions at times (think 90 degrees to the wind, or stern upwind). Sometimes the current affects the boat differently than the buoy.

As for the Z flag, my experience is that no one knows what it means, so everyone ignores it. YMMV...

Mike