Lots of nice work here Frank, and very interesting to me because it helps to confirm my recent habit of using my 70-200/4 for all my macro work. I use it either with extension or supplementary lens or both, and it gives excellent results, the working distance is much more comfortable, and the bokeh is superb.
I have been so pleased with this that I have tried using the 200-500/5.6 in the same way, also with good results. However, the lens is just a bit clumsy for this kind of work, as I'm sure you know.