I have never had Fat Beams on my current bass, but used them on another and loved them. I have Sun Beams on my current Jazz bass, and although they are sounding good with the right now i am wondering how they measure up to Fat Beams on the same instrument. I didn't know if they would be too much "brighter" than the Sun Beams. I don't really want something that would be too much brighter, but I would like a little less mid-range. I find round core strings seem to pop out the harmonics better for me, but if I had to, hex core would be OK.