I’ve had a set of those on a jazz for about 6 or 7 years, they did take a while to break in , probably about 6 weeks on and off, then they really mellowed and are even better now, I think I paid about £10 for them, bargain 🙂
I can’t help with roundwound strings as all my basses apart from 1 precision have flats, or tapes, I think @jazzyvee uses rounds, maybe he could advise 🙂
Might be worth asking if they will post, I really liked a precision a while back which was collection only way up north, and I asked if they would post and they said yeah sure 🤷♂️
I’m no expert btw 🙂, I only use flats and I like an incredibly low action, it sounds like the higher tension has pulled the neck a bit further forward, a few tweaks to the truss rod should do the trick