Hm... I surprised the clove hitch worked out for you. It's notorious for slipping. The tails go to the "far side" of the object being hitched onto. When the sail is sheeted in I would expect the knot to rotate, pulling the lazy sheet partly through/into the grommet and possibly loosening the knot. Do you have a picture of the attachment?
Clove hitches are not designed for permanent attachment.
I would expect the same from the constrictor hitch, but with much less chance of coming undone.
Most of my sheets are attached by a lark's head in the middle. If I started to experience chafe, which I haven't, I could cut the bad part of the line out and then switch to bowlines for a while.
1972 Catalina 27