I've had a Jack Casady for 4+ years now and I think I finally found the perfect match in flatwounds (at least to my ears and fingers). I tried Labella 760FL & FM allowing them to break in for about a year each set, and didn't get what I was searching for. I thankfully decided to give Rotosounds a chance with their Monel RS77LD and I really like their clarity and tension. They are bright as roundwounds right now, but I'm very impressed with the sound and feel after a few days. Gave the truss rod a turn and adjusted some saddle heights and they have a satisfying snap to them. Well see how they are once they go dead.
They will go dead quickly, quite known for that behaviour. I have played these strings in the past and enjoyed them sound wise, but not as smooth for my liking for flatwounds. Hope you’ve found your match, it’s a great thing when you do.