As I read the latest posts here, I see there is much commonality between the Schroeder Ref SQ and the TG tonearms.
The Schroeder’s string attaches to the top of the tonearm’s structure. The string’s endpoint attaches directly under the arm tube through an "attached-to-the-tube" convex magnet. Another magnet below, which appears to be a flat surface, attaches to the lower end of the tonearm’s structure. So no, the Schroeder arm does not pivot around a string; it simply hangs from a string as does the TG.
The key adjustment is the gap between the magnets. Frank’s documentation suggests that a business card gap works well. I have experimented with this and found that the shortest gap possible provides for the greatest bass extension. I start with the magnets close so that I can barely get the smallest feeler gauge through the gap. I raise and then lower the arm over an LP, and observe that the arm’s lowering down to the LP. With the magnets tight, the arm slightly shifts along the horizontal axis on its way down. I make very small adjustments to the gap until lowering the arm results in a smooth, i.e., no sideway shifting, all the way down.
I will leave it to the mechanical/structural engineers to debate the benefits of the magnetic coupling below the Schroeder's arm tube and no coupling below the TG’s arm tube.
I could not attach a closeup picture of the Schroeder’s string/magnet view here so I added such a picture in my virtual system page.
John