Nice grip frame,
just curious,,, what would be the budget?
This grip frame calls for some early walnut/blackbirds, or walnut/squashed birds. ($60-95)
Most of these grip frames went on Old Army's & were walnut/squashed birds.
But that not to say some nice CUSTOM Old Burl English Walnuts,($100-160) or Stags of some sort (Patrick Grasshorn $150-200) wouldn't be the way to go, If the budget allows.
...and then I would send the Grip Frame to the Grip Maker for A++ fit.