IMHO the ideal solution would be a H14 sail on a H16 boom. That solves downhaul/outhaul/sheeting angle problems. The stock halyard could be extended with a wire rope pigtail.
You are exactly correct. I used to do this years ago when I sailed both a 16 and a 14.
Now I sail a Hobie 17 and the 17 sail is a perfect fit on the Hobie 20 with a halyard pigtail.
