I don't know for sure. I have had good results with Cobalt Flats. Just make sure you don't get 'em too light or they will be way too floppy. They are easy on frets, and they are bright. I get a pretty good angry piano out of the '91 with those strings. It has Chinabuckers on it for now, until I get around to getting Thunderbuckers for it.
I tried the cobalt flats and they just tore up my fingers. That relieved my desire to try the cobalt rounds.
Rock star? I wish... 