Recording hz doesn't really matter in this instance, but it's best if your sources match, so make sure they're both set to either 44.1 or 48. There is a built-in automated audio syncing option in Premiere, so it's very easy to sync when editing.
Here's your whole workflow:
Make sure you're recording audio on both interfaces, so both Audacity and your ...
Press once the record button to start recording. Clap 3 to 5 times.
Import both video and audio into Premiere.
Align the peaks in the audio of when you were clapping.
Once you've done that, mute the audio that comes with video, and only enable audio that you've recorded separately.
I've also paid $200 or so for pluraleyes.
The way you use this is ...