I'm liking these strings even more. Even though it's only been a couple days, they have actually started to "calm down" and with the tone rolled back a bit on my Precision they're really nice and thumpy. More thump and a little more dynamic but still have this classic or old school flavor to them, and not as thuddy as GHS Precision flats.
I still like GHS Precision Flats, but I'm feeling that these Fenders may take over as my flat of choice. I'll give them a few months and see how they end up breaking in. Like I mentioned before, I also put a set of TI Jazz Flats on another Precision last night. Two totally different P Basses with different pickups, bridges, fretboard material, nut widths, etc (TI's are on an '08 American Standard with rosewood board and Nordstrand NP4, and 9050L's are on a '17 Classic 50's Lacquer P with an SD SPB-1 pickup) The Fenders definitely have more of that old school thump, while still having a tight, punchy low end. The TI's are a great string (this is my third time around with a set of TI's) and even though I like how they feel, they've never really wowed me sonically. Regardless of the bass they're on they seem to lack low end. As everyone knows, they are a bit mid heavy, but that's what they do. I'm going to force myself to just keep them on the bass for several months and see how they evolve. The TI's are a very polite string, while the Fenders are more authoritative, if that makes any sense. And just because it may help others, I only play with my fingers, never use a pick, have a pretty light touch, and always pick between the pickup and end of the fretboard. I never pick anywhere close to the bridge.