[Kwant] Units and volume for conductivity using KPM

Hello everyone, I'm having difficulty figuring out the correct units conversion factor for the conductivity obtained from the KPM method. I tried following the example for the Haldane model as much as possible. In the link, there is a minimal working example for computing the longitudinal conductivity for platinum https://github.com/bfocassio/ExampleKwantConductivity. I'm using a model derived from Wannier functions for bulk Pt in the conventional unit cell. The question is: Should I normalize the conductivity by the volume per site? (using the volume in m^3?) Are there any other prefactors that I am missing? The goal is to obtain conductivity in SI units.