Hi Raul,
You've posted in the past that the Graham 1.5 and its upgrades are just over-priced, mis-engineered knockoffs of the Audiocraft arm. I agree.
So I assume you're just trying to encourage a fuller discussion. Okay.
Tonearm wire/cable
The Schroeders (and TriPlanar) have single runs of wire. The Graham has multiple breaks and connections, and some of those connections are quite poor. Breaks in any signal path are electrical roadblocks of course. When the signal level is this low such roadblocks become audible. Neither a cartridge change nor any other change short of a hard rewire could alter this fundamental weakness of the Graham design.
Cartridge matching
The ZYX's are an excellent mass/compliance match for a Graham. 9-11 Hz in both modes.
Other cartridges
No one's heard everything, but we have also listened to Koetsu's and Shelters. Same result every time, with every group: the Schroeder wins unanimously.
Sometimes better is better.