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

Dear @sunnyjim : My response is: none.

As a fact exist no one AS mechanism that's accurate. It's i9mposible to have it in a totally mechanical imperfect medium with a pivoted tonearm.

Any one of us can say that we hear/listen better quality perfomance level with out any kind of AS or with AS at maximum or minimum but in all cases we are far away from true.

We need always AS ( if we use it or not is a different matters. ) problem is that what we can choose to do it is non-accurate including what @almarg  posted  and I refer to him with all respect.

Subject is very complex because we have to deal: with different recorded velocities at each LP and on each LP those recorded velocities changed at random at different place/distance in the overall LP recorded surface, we have way different compliance cartridges and this means not that we have low/medium/high compliance but different cartridge compliance figures over the whole compliance range that exist in all cartridges!, cartridges has different stylus shape tips and different level of quality of those stilus tips because some one are better polished than others and all of these has an influence of the AS needs ( I remember that in  one of my AT tonearms were 3 alternatives of AS depending of the stylus shape. ), off-center LPs ( all LPs. ) needs different AS, even the warps in LPs ask for different AS because at each single warp VTF change, exist tonearms that use damping oil like many unipivots or the SME or Triplanar or Townshend, etc, etc.

AS level is affected with each of those non predictable changes/parameters and some others.

So, an accurate universal perfect AS mechanism is non-existent yet.

Regards and enjoy the music,
R.

Dear @ct0517 :   """  Here the linear tracker reveals a very different soundstage, and it plays clean on the last songs of records .....very often the best songs ! But until you hear this in your own room to make a direct comparison - you don't know """

I did it with 3-4 LT in my system and listen on very well know friend's systems and yes the soundstage sounds different but nothing that really matters enough to pass from pivoted to LT tonearms and soundstage can " sounds " different for other factors as simple as the material or combination of materials used on the tonearm manufacturing by design. Soundstage comes not because an intrinsic LT characteristic but for several other factors.

LT units are imperfect ones nothing is perfect and LT has its own trade offs.
If the magic " key " on tonearms was  the LT design then you can be sure not only me but any one used to own it instead pivoted tonearms.

Perhaps AS is the least important parameter/factor involved in the very complex cartridge/tonearm/accurate set up/LP quality level performance including that "  it plays clean on the last songs of records " that we  can have with pivoted tonearms too.

As everything in audio LT is an alternative but till today pivot tonearm is the " king " of the tonearms that surrounded almost all audiophiles and for very good reasons.

LT works for you, good for you, have fun with!.

Regards and enjoy the music,
R. 

Dear @ct0517 :   """  7,630 posts Raul and not one that I have seen that offers to share information or shows any ability to set up a LT tonearm.  """

I can't understand why you " insist " with the LT subject, no one but a few use that kind of tonearm design. Tonearm designers deciding go for the pivoted ones. Kuzma owners of Kuzma LT tonearm change it for the pivoted 4P.
Analog experts as M.Lavigne or A.Porter changes theirs Rockport Sirius and Walker both with LT tonearms and today use pivoted tonearms with out the need to turn around again for LT designs.

With all my respect to you in your system you just can't be aware of the LT limitations against pivot tonearm designs because for that first you have to own first rate top pivot tonearms not those non-damped very old designs that are not a good example of what a pivot tonearm " means ".
In the other side the levels of IMD in your system is just to high to detect real limitations/advantages. Why? ( I take the information from your published  virtual system. If already changed then my comment is out of focus. ):

those 800 speakers comes at least witjh two issues that goes against top quality performance level: exist in the music signal information an equalizer/filter where that signal information is degraded and if that device is not used then low range speaker response can't meet B&W specs.

In the other side those 800 woofers handle from aroun 300hz and below it incrementing the IMD aside that the FBP 600 was not designed to meet exactly and cope with the specific woofers characteristics. Here you can read about:

https://forum.audiogon.com/discussions/do-you-think-you-need-a-subwoofer/post?postid=310058#310058

If in the future you make a test in your system integrating two active subwoofers in exactly what I posted in that link you will be nicely surprised. You say you are willing to learns, well this is an unexpected opportunity where I'm totally sure you will have NO comeback/NO return after test it. 

Anyway, till today I don't need to change to LT tonearm design so why bother about?, I don't care about and as I said: " AS is not what can makes the differences between both kind of tonearm designs.

As I told you if you are happy with your LT design good for you, I prefer pivot tonearm design.

Regards and enjoy the music,
R.

Dear @ct0517 : I will do.

Btw, I'm always willing to learn and improve my ignorance level.

Regards and enjoy the music,
R.

Dear @ct0517 : I forgot, regarding the 800 set up I think you are using tube amp along the FPBs: is it in this way?

Thank's in advance.

Regards and enjoy the music,
R.