nc8000
Headphoneus Supremus
Well I'm assuming you're only running them off the ZX2, and are not connecting them to a PHA-3. In that case you want a 3.5mm TRRS balanced for Sony ZX2 termination, and a Noble type IEM (which is 2-pin).
If by any chance you have a Sony PHA-3 connected to the ZX2 as well, then you might go for the dual 3.5mm termination, but doesn't seem like you do.
That is the problem with balanced, there is not one standard but at least 5 or 6 diffrent termination types
2,5 mm trrs
3,5 mm trrs
Dual 3,5 mm trs
Kobicon
Hirose
A variety of xlr terminations