My measured results were only for Delta 100 developed in Thornton's with 12g/L metaborate for 4 min + 4 min 70F as per Edge of Darkness (ED), agitating 2 initial inversions then 2 inversions/min. This gave EI=80 ,average metering,sun/shade.
In ED p94 sodium sulfite was reduced to cut down grain dissolving activity and increase sharpness so it would be expected that increasing sulfite again would have the opposite effect.
The link indicates longer times in A increase contrast,ED p95 notes that increasing metaborate does the same.
At a guess it seems quite likely that EI=50 or EI=100 could be obtained by varying the time,at least with Delta 100 and quite likely FP4+.If the contrast is not satisfactory it might be adjustable by varying the alkalinity,metaborate concentration, as Thornton suggests,only experiment can tell if speed and contrast can be balanced in this way, I have not seen results from others on this.