Music First Audio is a subsidiary of Stevens & Billington which is why their products use those transformers in their design. When S&B used to let people use the transformers for DIY and OEM John Chapman at Bent Audio built a very nice passive preamp with them and when S&B pulled the plug on DIY and OEM he switched to the Slagle autoformers and developed his own module with relays. If you can find one of his preamps used it would be worth trying out.
I have and have had many passive preamps over time that used quality attenuation controls. Everything from a simple pot in the box using NOS Noble potentiometers to Khozmo, Slagle AVC, and S&B TVC passives (all of which I DIYed and all had dual mono attenuation). While all of them performed well for me, the best bang for the buck in my opinion is the one I didn’t DIY which is the Lightspeed Attenuator.