Now it's my turn to apologize for my absence. My harddisk gave out last week (no data lost - the back up system had its finest hour) and before I had it replaced and restored, I had seen a few days.
First I reran the
Drosera-glands stack using DMap and a more aggressive percentile setting. That improved matters indeed. Most of the harsh blotches in the droplets and behind the second green arrow have gone. In fact, where the result is good, tonal transitions are smoother than in the PMax result.
Foreground-background issues remained of course and more conspicuously than in the PMax result. But now this is not a composition that I would readily choose again.
As for the mini cololour checker: yes, that would work for the MP-E65. However, my studio lighting doesn't change so often that I clouldn't do a part-wise reading of the full-size target and save $150.
But yesterday I have put together my Mitutoyo assembly and that has a field of view of less than 2.5 mm. No target will ever be that small, so here it's only one patch at a time to help me out.
(In fact, I am inclined to the opinion that a this magnification I would just as well not use colour management, for no-one ever will see the object in real life without any (unmanaged) optical aid).
thanks for your help,
--Wim