The choice depends on the diameter, strength, and spool length, ranging from 15 to 50 m depending on the model. A thinner diameter allows the lure or bait more freedom of movement; a thicker diameter provides more material to withstand abrasion.
Take care when splicing the line to the main line and tying the end knot. Inspect the section near the hook after a fight or if the line has rubbed against a rock: while fluorocarbon is abrasion-resistant, a damaged line is not reliable.