What is more accurate: magnetic anti-skating, or barrel weight attached a fishline?

Andrei, Here is how I think of it: A conventional pivoted tonearm is always set up such that the stylus tip overhangs the spindle.  Now think of the relationship between the tonearm, the radius of the LP (from stylus to spindle) and the pivot to spindle distance, as 3 sides of a triangle.  In order for the stylus/cantilever to be tangent to the LP groove, there must be a right-angle triangle formed such that the tonearm and the LP radius are sides A and B of the triangle that must meet at 90 degrees, per the Pythagorean theorem.  In such a triangle, the pivot to spindle distance is side C, the "hypotenuse".  Pythagorean theorem says that the length relationships of sides A, B, and C in such a triangle must be such that C-squared = A-squared + B-squared.  But, because the pivot to stylus distance is always greater than the pivot to spindle distance, when you posit overhang, this condition can never be met.  Thus, for a conventional pivoted tonearm, the stylus/cantilever can NEVER achieve tangency to the groove.  Headshell offset is a band-aid that permits tangency at two points along the arc traced by the stylus, but as noted above, headshell offset per se creates a geometry whereby there is still some skating force even at the 2 points of tangency.

@Raul
no. not together. They represent two options for running. I am just up north fishing. I will answer your question in more detail on my virtual system thread.
The cool lake environment is keeping me from wanting to go home where it is 35 degree C with the humidity 40+ Celsius weather. Watching the Rio Olympics very interesting to see green pool water and only 18 degrees Celsius. A cold front........Well it is winter there.
 

I agree with the possibility that some uni-pivot arms can be somewhat stabilized with the use of anti-skating.

I don't find it plausible that the use of fishing line on some anti-skate mechanisms will somehow stretch over time. We're not talking about tons of weight here folks Gimme a break! After all, these designs have some adjustability for an extreme worst case scenario.

What is the perfect scenario? (assuming in this scenario, there is no R/L channel distortion).

When one raises then lowers the arm down into the lp groove, should it arrive in the same place from which it was initially raised? This would, I assume, allow the arm to move toward the center of the lp by forward motion of it's tracing the groove in the lp.

Is there the thought that more or less artificial force is needed?