First off, Thank you matt for taking the time to do this test for us. It is really appreciated!
It's so hard to conduct a test like this given so many option not knowing which is the standard to compare. In my experience I am going to take a guess that the original 1073 is D or A. D was darker sounding than the rest and A was the second darkest. They sounded very similar to one another especially in the midrange area.. C was the thinnest and most unappealing in comparison. B was a mixture of C and D.
So my guess is as follows
Let me also say this, in a mix, I honestly don't think I'd be able to tell the difference between these.