Make a whipping on the end of double braided ropes to keep core and cover together.
A tapered line on the J70 can be useful to reduce the effort to hoist the sail. Make sure to select a double braid line that includes UV protection of the inner dyneema core. Observe the J70 class rules that specify the minimum line diameter.
A Brummel Lock-Splice is great for providing a dyneema eye loop that won't slip. Perfect for the Jib or Mainsail Halyard.
This technique is required if your line is run through the mast or the far end otherwise inaccessible.