However, unless someone who has used the same developer gives me the exact formula for a totally equivalent alternative after having experimentally ascertained the claimed equivalence, I'm not going to spend my time on it.
Raghu, yes... that would be for example the Xtol vs Mytol case, that is ascertained equivalent, or many other matching formulas in the FDCB.
... but anyway what I want to point is that we have two approaches:
1> I want that developer because it is fantastic and it does that...
2> I want to control what a developer does to adjust the result to what I want to craft
IMO the second way is a mind openning situation, we may get the same result in many ways. For example, the OP does not want the Rodi grain nor the Xtol grain... So IMO it is not important what Rodi or what Xtol does, the important thing is that we may add sulphite to Rodi or diluting Xtol. A bit it's the archer and not the arrow. Just a thought...
Still, there is nothing wrong in using a film-developer combination that yields what one wants, of course !
Xtol is as sharp or sharper than Rodinal.
...sharper, probably (but it depends on what we call sharp)