[Freesurfer] geodesic distance calculation

Dear freesurfer experts,

I'm analysing functional data using fsfast running under freesurfer-Linux-centos7_x86_64-dev-20150728. After streaming out the maximal activated cluster using mri_surfcluster, I want to calculate the geodesic distance between these vertices. Can I do this with mris_pmake using sphere.reg as surface?

Furthermore, I would like to evaluate symmetry between the hemispheres. I would like to mirror the maximal activated vertice of a special contrast of the left hemisphere to the right hemisphere and calculate the geodesic distance between the mirrored coordinate and the maximal activated vertices of the right hemisphere. Is there a way to do this?

Best regards, Desiree