Genuinely curious — how would the white gold JUC look any more “off” on you than your Tank Francaise, since they’re essentially the same/similar color metal? To be clear — I think your TF looks fab on you, not “off” at all. And I love mixing metals; think your stack looks great! I think either option would work, but the WG JUC could add some balance, since your other two bracelets are yellow gold. Especially if you plan to sandwich the two YG bracelets between the WG tank and a WG JUC so you’d have WG on both ends of your stack (altho in reality they’d probably jumble together when worn).
Ultimately, though, you should pick whichever one you’re drawn to and not worry about what others might think … you’re drawn to it for a reason and I find that going with your gut or your heart in these instances is usually best! 💙