As a "super-macro" lens, reversed, all the previous macro images (several weeks ago, way up top) were shot at f/11 - f/22
Having shot at multiple other apertures with it, the best macro aperture, reversed, is f/8. (Retains the most vivid color + most pleasant bokeh.)
I will post some results to show the differences in bokeh, reversed.
The first image (below) is a 2-image stack of a small fly @ f/11. It is razor-sharp, but the diffraction ruins the bokeh.
The next 3 images are just random, single-image shots, taken @ f.8, to 1) show the incredibly-shallow DOF, 2) to underscore why stacking is necessary, and 3) to show how much better the bokeh is @ f/8 than f/11+.
The final 2 images are 4- to 8-image stacks taken @ f/8. One is at 2:1 the final is a 4mm spider taken at nearly 5:1.
By doing mini-stacks @ f/8, you get the best of both worlds: some appreciable DOF, but also the retained color and bokeh qualities.