Having learned before anyone heard of (or at least wrote about) "stand" development I still find that a bit odd
In my lab I have a brochure about stand development which was written in 1914 if I recall right (for sure before WW had ended). I bought it in a Vienna antique shop 10 years ago.
It makes reference to Rodinal and I think it was written by Agfa in Berlin Kreuzberg SO 36.
Before they moved to Rummelsburg they were located in Kreuzberg. Then they moved to Wolfen, then partially to Leverkusen, you know the rest...
I am sure your negatives are more than fine Roger. If you control highligts and compensate by a bit with extra exposure and control your process you will have perfect negs, for sure better than those of 95% of the others.
On the other hand however someone who´s new to the business and does not know about all these things is well off with a developer which yields the speed (most cameras tend to underexpose), equalizes the negative contrast and gives him a bit of sharpness and grain for the classic look.
He´ll most likely be using a simple tank with less options of control than you have so the equalizing effect of the "stand development" (it really isn´t yet) adds a bit of a bonus for him.
So FX-39 will hoepfully find his fans and you please stick to Diafine
Mirko