Michael Poche
Poster Extraordinaire
I am wiring up a humbucker for parallel/series following this diagram and I want to confirm that the GREY wire is the bare shield, not the white... correct?

Yep, it's a Seth Lover; thanks!Correct, assuming you're using a Seymour Duncan pickup. The wire colors are not universal. Here's a translation guide in case you're using something else:
https://madhatterguitarproducts.com...-tone-shaping-system-wiring-sheets-references