The Geoffrey Crawley formula Gerald Koch mentioned is FX-16 (Grain texture developer for high speed films).

See the 1963 formula reprinted up to about 1987.

It seems to be a modification of FX-2, using metol and glycin as the developing agents. Pinacryptol Yellow was the original preferred restrainer, although Crawley said you could substitute potassium bromide for slightly "fluffier" grain. Whether it makes much difference with modern films (compared to Kodak Royal Pan-X, which must have been what Crawley mainly meant it for), might be worth testing.

I never really used it much and would also like to see a controlled comparison to Rodinal.

-Philip Jackson