If a 3/16 halyard is "too hard to pull" there are other problems.
Usually this is battens are in too tightly, and/or binding on an old sail: I have moved the luff batten end caps forward about 1/4 inch by making new holes for the machine screws. This keeps the cloth luff tape from "wrapping around" the sail track and binding.
Also use McLube spray if the sail track is cleaned first.

The clue word here is "old sail"