Dude your killing me, that lens is my baby.
I am impressed with the bee photos and how that little guy performed but I don't think you gave the 90 enough justice in the first shot with the bottle opener.
Either way I agree as I DIY like the best of them. Nice post and good experiment.
If you haven't traded the 90 in yet. I have the raynox 100 and 250 adapters. That can give you some more versatility. If you try to stack them it is pretty much impossible handheld as the focus plane is so thin you need to be on a tripod with a focusing rail and then stack. I'll try to post some things I am working on with it.
Again good job, but made me so sad.
A more fair comparison would've had me set it to f5.6 or so and up the ISO. But I was a bit disheartened as well. Have you come across this Light camera? https://www.light.co/ (the everything killer)