My observations on 12" vs 9" and anti-skating.
A well-fettled slate 401 with 9 and 12" Jelco TK850 tonearms.
The 9" has a slightly more incisive bass and tempo. Almost a CD quality to its delivery across all frequencies. Best for rock and electronic. The 12" goes a little deeper, has better dimensionality, naturalness, sweetness, air and space, with finer highs. Best for jazz and voice.
I do not use anti-skate on the 12" except when there’s a warp or dimple. It simply sounds better with it off. Note that I use London-Decca cartridges with no cantilever which likely impacts how AS impacts playback.