No problems at all with Hammer bite on my T120, but if I did have that issue with it, what I would first try is gluing a strip of black neoprene just under the Beavertail.
I had that issue with my old Walther PPK/S .380 and a Taurus PT945 (long since traded off) and glued a strip of Black Neoprene under the Beavertails of those Pistols.
It helped quite alot. I used to carry both of those Pistols, but the Walther has been semi-retired in favor of 9mm Striker Fired Pistols, which have no hammer to bite or poke me with.
As to your original question, I would not remove much material from the underside of that hammer, but you could probably get by with just a sliver more, of about .005 inch.
Resale value of your Pistol might suffer a bit from such modification, if not aesthetically done.
You might also want to work on your Pistol hold, Weaver or Isosceles Stance, with the two handed hold, a bit more firmer with the forward support grip being a bit stiffer.

Note pad glued to the underside of the Walther PPK/S (right)