You want to cut the line at the length you can aerialise optimally. If the line matches your rod this means about 10 to 11 yards of head.
Remember that if a rod is rated at a weight 7 say, it means it can aerialise 10 yards of 7 weight line.
In the old days I would then needle knot the line to flattened mono backing about 25lbs bs. You want about 50 yards of it.
These days I would buy some of the special shooting backing supplied by Airflo. You can also use hollow braid but it tends to burn your fingers when a trout opens the throttle.
Inch-worm the braid onto your line and then locate with a sleeve. Then apply a few touches - not too much, of super glue and it will never move again.
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