Personally I think braided line with copolymer leader would be the optimum for the C-rig if the structure/cover you are fishing will allow for it. Here on Ky/Barkley I would stay with strictly copolymer as the chunk rock and mussels here will shred the braided line. I know some folks profess using a florocarbon leader but to me that makes no sense...to use a sinking line on a technique that I want the lure to suspend more or fall slowly.

As a note, I use 20lb Gamma copolymer main line and 12lb Gamma copolymer leader.