ahah, I know, it's really expensive! since I discovered my love for flats, I've tried Chromes, Rotosound, Fender, LaBella, Pyramid and Thomastik.
as I said answering your first post, I'd go straight with LaBella 0760M, to be sure. they are "The" flats heard on countless records, and still the most used worldwide.
usually when I'm looking for a specific sound, in particular if clean and knowing the used bass, the first thing I look at is strings.
usually when I fall in love with a particular sound, knowing wich bass was used, I figure out the strings and try them.
for example, my love for Thomastiks started three years ago: I was listening to "Try!" by John Mayer, the live album with Pino Palladino: a Precision with those Thomasik flats.
I bought them and fell in love with their sound, their feeling, and since March 2011 they are still on my headliner Precision: here's an example:
then I found out that Paul McCartney sticked to them after years of research for the strings to use with his Rickenbacker, because he claims that they are the only strings giving him the sound he had back in the 60's with the Maxima flats (discontinued in the 70's). being pure nickel wrapped and with low tension, they can give exactly that "rubberish" sound Paul had in albums like Revolver, Rubber Soul, Sgt Peppers...
another love of mine was the sound from John Paul Jones, and with him there were James Jamerson, Donald Dunn, Joe Osborn, Carol Kaye, Paul Simonon (since London Calling), John Illsley (on the firs two Dire Straits albums), Tommy Cogbill and Garry Tallent; I found out that they share(d) the same set of strings, those thick LaBella flatwounds now known as "the Jamerson set", the "Original 1954". I had to try them, but I feared the gauge, being used to the slim TIs...
so before falling in love with them, I've tried many times the Chromes, then the Rotosound, the Pyramid and the (new) Fender, but it wasn't "that" sound.
a month ago I decided to try them, and now this Precision string with LaBella is my main bass for everything, from live shows to recordings...
it all depends on the sound you are searching for, and since you cited John Paul Jones, I guess you should try them:
they sound exactly this way on a Jazz Bass.
here's another example on a Jazz, played with a pick: