Best setting for oppo udp 205

Can anyone tell me the best settings (in Device Setup Advanced) for highest sound quality when using an Oppo UDP-205 as an end point.
FYI -I have it running straight from the balanced outs to my preamp, but as an option can also run digital out of the hdmi and into a Playback Designs DAC if necessary.
Just wondering if the default settings are best or editing in some way for better performance.

I have this same issue as Roon only outputs 2 channels and no signal for a subwoofer.