Harry
You can dilute T Max developer, like HC-110 or Rodinal, and slow the process.
THAT means that you can link the highlight density to agitation.
You can balance the development time (which places the shadows)
with the agitation (which places the highlights).
The biggest influence of 'bad grain' is from too much contrast & over development.
If you can reduce the development, you'll reduce the appearance of grain.
Here is an overlay of Kodak's curve set of Xtol 1+1 (in red) over the Tmax developer curves.
It shows pretty clearly that Xtol (1+1) gives a higher shadow speed that TMAX,
which translates as shadow detail. You can find the Xtol data at:
http://wwwfr.kodak.com/AT/plugins/acrobat/de/professional/xtolEntwickler.pdf
The curves are at the end of the document.
D-76 1+1 will give the same speed as TMax developer, but a less contrasty image. Look at the TMZ pdf from Kodak to compare D-76 and TMax developer.