I neglected to answer the bit about my favorite formula. I always make dual sheets so I have a backup and some darkroom options. For film, my pecking order is : first for all films, Germain's Finegrain (can't buy it). For T grain film and ir, my second choice is Fx37 (can't buy it), For TriX, FP4, HP5, and most old fashioned emulsions, a Rodinal clone I call Ianol (can't buy it). I also keep D76H and Pyrocat MC on hand as additional variables. I use Ilford WtFb for printing and my paper developer is a cool tone Ansco 130 which has some variations (can't buy it).
Happily, this has let me try a huge variety of other chemical approaches rather than speculate or rely on forum posts for information..hate not to really know things first hand..

P.S. And it's fun!!