I used some Heavy Lo Riders for the first time on my Fender P Plus. I loved them at first, but after a few shows and practices, they started buzzing horribly. I have yet to find a string that I like. I think Lo Riders may have just been too heavy. I decided to try some flats. I threw on some D'Addario Chrome Mediums. I really like them so far, but they aren't broken in yet. The action is good, but is it just too low, and that's why the DR's were buzzing?