I am also using the arche headshell on the 1200G, with the very low compliance London Reference cart.
Aside from the convenience of easy overhang, SRA and azimuth adjustment, the weight (17.5g) and damping ability of the arche (and tighter fit into the collet) has helped to eliminate the mechanical quirks of the London cart. I also wrapped the arm pipe with 3M foil damping tape, and installed the KAB fluid damping system. The result is exemplary tracking, greatly reduced surface noise and spectacular sound quality.
Aside from the convenience of easy overhang, SRA and azimuth adjustment, the weight (17.5g) and damping ability of the arche (and tighter fit into the collet) has helped to eliminate the mechanical quirks of the London cart. I also wrapped the arm pipe with 3M foil damping tape, and installed the KAB fluid damping system. The result is exemplary tracking, greatly reduced surface noise and spectacular sound quality.

