Default record quality was only an option for analogue recording. With most systems expected to be digital now, it's not a user selectable option, as it's based on the broadcast quality.
The NPVR API still supports passing it in.....NEWA allows you to set a default which will be applied by anything set to record from the NEWA interface. This is set on the Config tab. It simply sets the selected recording quality on the NEWA record pages which is then passed into the API call to do the recording.
I am not sure if NPVR does anything with it for digital recordings or not.....but it is settable via NEWA. You can also override the pre-set the quality with individual recordings from NEWA as well so if your default was Best you could set an Event or Series to be Good simply by changing the default value on the record screen.
Intel Core i7 @ 4.00GHz Skylake 14nm
ASUSTeK COMPUTER INC. Z170-DELUXE
Windows 10 Pro x64
PVR Software: NPVR 5.1.1
SiliconDust HDHomeRun HDHR5-4US Connect Quatro 4 Channel Tuner
Roku Ultra
2 PCH A-100's