Digital Newb with a couple questions

Guys-

I am trying to optimize my digital setup and just bought a Matrix Audio X-SPDIF 3 USB optimizer. I have two questions about this addition.

1. It will be linked to a Denafrips Terminator II via I2S. The X-SPDIF 3 has switches on the underside of the chassis that can be changed to match the configuration of the DAC's I2S. How do I find out the configuration on the Terminator II's I2S and then translate that to the settings/switches on the X-SPDIF 3?

2. If my gear consists of

Ethernet Cable=> NODE => USB cable=> Matrix Audio X-SPDIF 3=> I2S cable=> Terminator II=> XLR cables=> Preamp...

then which clock is running the show? The NODE's? The Terminator II's? The X-SPDIF's? 

Thanks.