Well, I got my Jamersons this afternoon and quickly slapped 'em on the '73 P, replacing the 10 year Chromes I had on there. I was fully expecting months (if not years) of breaking in before they mellow out, but to my surprise they're fairly mellow out of the package. they cut through, but are by no means trebly or crisp. To the naked eye, the string gauges look the same as the 50-105 Chromes I replaced, even though they're supposed to be much heavier, so my fear of playing "bridge cables" was put to rest. Yes, the tension was high at first, but after I set up the bass for them and stretched them out a bit they really didn't feel much different than the Chromes, IMO. In fact, I even raised the action a little to get more thump out of the tone.
Amazingly, my playing felt and sounded smoother, with less noticeable fret click clack and an overall improved tonal balance across all strings from the 10 year old Chromes. Fatter but with better clarity ad detail, but no harsh offensive top end, even with the treble cranked. My P really sounds like a P now. So if you're a Chrome player now, don't let the high tension string gauge comments scare you off, because with a proper setup (which you should be doing with any string change) they really feel comfortable and smooth, IMO, especially if you're a current Chrome player.