@holmz , Frank Schroder and Peter Ledermann have been friends for a long time. Peter's demonstration rig has a Schroder Reference Arm on it and there must have been 4 or 5 other Schroder arms hanging around when I was there.
I am not sure about a transformer with Soundsmith cartridges but you certainly do no have enough gain for a Sussurro. But, what you do have enough gain for is The Voice which is nothing more than a high output Sussurro. Same stylus, same cantilever same drive mechanism. The only difference is the coils have more windings and the compliance is set higher which is the problem for you. At 22 um/mN it might be too soft for your arm. It works perfectly in the Schroder CB. Using the Certal plate I get a horizontal resonance frequency right at 8 Hz.
With a larger arm like that you really need a Phono stage suitable for low output cartridges. There are several really good high output cartridges out there but the majority of them are mid to high compliance. I think the Nagaoka MP 500 has a lower compliance but I am not sure. You have any number of directions you can head in. I am not a big transformer fan. I do not like more contacts and interconnects in the way of the very low signal from the cartridge. I think if you want to go with a low output cartridge you should upgrade your phono stage. If you want to go high level you will benefit from a lighter arm. @rauliruegas seems to know more about your arm than I do and he might be able to add more advice.