I think there won’t find a Bohr-Weisskopf effect (nuclei finite size depending contribution).
The Bohr-Weisskopf effect, it is clear that depends on the finite size of the nuclei, because depending on the nuclear volume, the interaction of the hyperfine field of the electron cloud with the nuclei will change. But the thing is that if the nucleus is spherical, and the electron cloud stays outside the nuclei, the r1 smaller than r2 conditions remains, so no overlap correction contribution will appear, because with the dipole terms of the multipole expansion we are already describing correctly the system. .