He was eaten for dinner, so this is his last portrait.
Thanks to all for the various suggestions. I think this is a bit dark (perhaps need a reflector of some sort on the other side), and alas, not quite enough depth of field to get the whole thing in focus... But! I did overcome (or at least understand a bit better) a couple of issues. The background has a lot more light than the avocado and the I used spot metering on the avocado, so the background stayed white without post-processing adjustment of levels. But the backdrop posterboard is quite a bit further away, so the reflected light did not create a rim. I do see an area in the lower left, but I know (now) that this is from the light reflecting off the white surface everything is sitting on. That would be easy to fix I think by setting it on a darker surface. The light is also slightly diffused with a white handkerchief over the light itself.
It's a bit darker than I wish.
I am sure glad you know what you are doing because it all sounds so complicated to me! Nice shot of the avocado but I agree it seems a little dark! Bon apetit
a small piece of aluminum foil with the shiny side facing the right or darker side would have given some definition to the surface of that darker side. i hope you didn't damage the avocado much.