I trialled the droplet style on a couple of projects and found it a bit fiddly - in the end I just used single text objects and set the background colour to contrast with the wireframe and used a round-cornered fat stroke which matched the background - it looks like a circle object with a text object positioned/grouped, but much easier to handle.

In a recent project I went even more minimal, using a solid dot with a line connecting to the relevant note. The dot was a good 2 or 3 times thicker than the wireframe lines, so they stood out without drawing a lot of attention. The advantage to using this method is I don't need to worry about skipping/doubling up on note numbers as I remove/add annotations.

I'll scrub the client details and submit soon.