The OP has an interesting project going that I'd like to learn from.
In an AudioXpress (April 2007) edition, Dennis Colin had a project that used a couple of LSK389 in parallel whose output was fed to an AD797AN opamp. He claims around a 1nV/sqrt(hz) referred input RMS noise performance. Later (Sept. 2007) he published an RIAA preamp using a similar (very low noise) topology.
Another diy'er claimed that Colin's design could be improved by using a very low noise DC power supply as the circuit hasn't got super high power supply noise rejection. I'm not sure if these 'tweaks' are noticeable in actual use, as some of these ideas end up in specmanship debates.
Peter.