A more interesting comparison may be to DK-50, which was considered not to be a fine grain developer, but to produce moderately fine grain in its era:

Metol 2.5 g
Sodium sulfite (anh) 30 g
Hydroquinone 2.5 g
Sodium metaborate 10 g
Potassium bromide 500 mg
WTM 1 l

DK-50 has about half the metol and bromide and about twice the metaborate and sulfite (very roughly).

The sulfite in the BJ formula is not sufficient to exercise very much solvent effect, so the fine grain must come from the metol and bromide acting together.