Anchell & Troop's TD-201 Two-Bath developer is (in my opinion) the best two-bath developer with current BW films.

Here is the formula
A
Metol 5gr
Sod. Sulfite 100gr.
B
Borax 2 gr.
Sod. Metaborate 5gr
Sod. SulfIte 6gr.
Sod. SulfAte 40gr.
--A 3mn + B 3mn, with continuous agitation in both.

However, I would like to improve sharpness reducing Sulfite in A.
I tried to use Thornton's formula for A (metol 6.5 gr + Sulfite 85 gr.), but I noticed a loss of activity with a lack of contrast.

So my question would be:
reducing Sulfite by 25% in A (to 75 gr.), how to ajust the proportion of metol in order to maintain the same level of activity than with 100gr. of Sulfite ? Increase metol ? add a pinch of Borax ? something else ?