I would also go with fluocarbon on the casting reel but I also use braid on my spinning reels with about a 3-4ft fluro leader. I've put the setup through it all and have no grooves in my rods eyes. I do believe that eyes made out of a certain material can groove but most do not. Most guys today that I know use braid on their spinning rods, as it eliminates line twist and is very sensitive.