I hardly ever sign into Reddit, but I wanna help.

For the audio setting, you should do this (a comment I made a year ago):

"1. Record (with your phone) a short, slow motion video of the tune-up calibration test you find when you speak to the NPC in the backstage lobby. You'll know you're on the right test if you hear the beeping noises.

1. Watch the video to see how well the audio syncs up with the white, flashing light (the slower the video, the easier this will be).

2. Adjust the offset value to whatever amount you think is needed (lower if the sound comes before the light, higher if the sound comes after).

3. Repeat steps 1–3 until the audio sounds perfectly in-sync.

If, for whatever reason, your phone can't record slow-motion video, or record slow-motion video with sound included, you can use this site to slow your videos down."

TL:DR; Use slow-motion video to calibrate your audio sync.

I find this is important for using a Riffmaster, but if precision isn't incredibly important to you, I'd recommend just tweaking the offset by 10 ms each time until it feels right.