See my response to the thread below which I think is in a similar vein
You’ll need to play around to see what works best for how you want to display and search this. I’m not clear if you want to see the data top down (session, recording, person, guitar) or bottom up (guitar, person, recording, sessions).
Without trying to build this it’s difficult to advise which elements should be data types and which should be properties. I’d recommend trialing several different approaches to see which works best for your needs. It’s only through trial and error that you find what works and what doesn’t.