I put a set of Martin Retro's (.011-.052) on my 522 12 fret about 3 weeks ago. I think my impression was the same as yours, somewhat bright at first but now they are really starting to sound sweet as advertised. Great clarity and balance, these will be a keeper for this guitar.
I'd like to try the JP nickel strings and compare them to the Martin Retro's.
[/quote]
Sprintbob.....yeah, the nickels are completely diff than the elixers for sure.....I don't know much about string "tension" when strung to pitch, but I know those Martin Monels really string "tight"....to where when I play that 520 with those monel mediums and then play my elixer mediums on another guitar, the elixers almost feel like lights, loose and flexible, if that makes any sense...my next two strings I try will be the JP PBs and their nickels, like you said.....awesome how strings can tweak that final sound we get from our favorite guitars!