Glad to hear the method worked!
But I want to give a bit of a disclaimer. Looking at Surfer's documentation, their Linear semivariogram does not support a Nugget (which is kind of strange), and they default the variogram slope to 1 without setting a range or sill. This essentially means that the semivariogram starts at 0 and increases with a slope of 1 forever (in ArcGIS, setting nugget=0 and the range and partial sill to the same very large value reproduces this behavior). However, there is no reason to think, in general, that nugget=0 and a slope of 1 are good values. So, the workflow I presented will reproduce the defaults of Surfer, but there is no reason to think this model actually fits your data. You noted this in your first post, but I just want to reiterate it because it's very important.