Hi, Neuro-
The std.60* has a resolution typical of EPI data (~3mm edges) and the std.141* has resolution typical of anatomical data (~1mm edges). Again, these are quite approximate and not constant. So, you could repeat the above steps wtih std.141* surfs instead of std.60 ones---note that you can't mix the resolutions of the surfaces in different steps here!
... However, regarding the distance scale that you would like to resolve: umm, did you acquire your data at a super-high resolution? Most anatomical vols put into FS are acquired with a voxel size of about 1 mm isotropic voxels; maaaaybe some folks get 0.75 mm isotropic or slightly higher. And voxel size determines the minimal possible scale of distances you could measure, under *ideal* circumstances---note that all MRI has noise, and all algorithms are imperfect, sooo, I don't see how distances that are an order of magnitude (about 10 times) smaller than acquired voxel size could be resolved.
For the grey-white boundary, you might want the WM surface (std.*.white.gii) or the smoothed version of that (std.*.smoothwm.gii) instead of std.*.pial.gii; the numbers for either of those WM surfs will be quite similar.
--pt
