What tracks offer the best left right separation?

lots of spatial info in bass notes including fundamentals and harmonics. You can always tell the multitrack electric bass “ experts from those who have a bass capable of high a, or something acoustic recorded in reverberant space . There is a LOT more to excellent bass than a forest of subs…… Where is Duke anyway ?

For a master class in L R C separation few if any have duplicated Rudy Van Gelder and his work w Blue Note.

Pink Floyd. - Dark side of the moon  

You and Your Friend - Dire Straits 

Separation is not a part of live music as, unless you're lying face up on the stage, blend is what live music is about. Even in situations with minimal or zero sound reinforcement you're not erecting a wall between instruments (except the plexiglass barriers here and there). I've mixed decades of live shows for money (yes, I'm a mix slut) and the only thing I put in stereo is  sometimes a tiny bit of stereo reverb which fools the audience into thinking they're having more fun.  Otherwise the art of panning things together in recordings is what gets the mojo happening.

Try Yello.