What my Nacra 5.7 originally looked like. You can simply reuse the wire block,(hang it from the pigtail) & stay with your original wire halyard.
The block with becket is the original 5.7 setup. When the jib is raised the block is about 1' from mast base. The bowline was tied to the becket so as to leave a 2' tail. This tail went through a cheek block on the mast, back to the block, then to a mast cleat, giving 3:1